What Are Core Web Vitals?
Core Web Vitals are three metrics defined by Google that make a website's user experience quantifiable. Since 2021, they have officially been factored into Google rankings, making them not just a nice-to-have but a business-critical factor.
The three metrics at a glance:
| Metric | Measures | Good | Needs Improvement | Poor |
|---|---|---|---|---|
| LCP (Largest Contentful Paint) | Loading speed | ≤ 2.5s | 2.5-4.0s | > 4.0s |
| CLS (Cumulative Layout Shift) | Visual stability | ≤ 0.1 | 0.1-0.25 | > 0.25 |
| INP (Interaction to Next Paint) | Interactivity | ≤ 200ms | 200-500ms | > 500ms |
Important: All three metrics must reach the "Good" threshold for Google to classify your page as performant. It is not enough if only one or two are green. Test your website now with our Performance Checker to see where you stand.
How Are CWV Measured?
Google distinguishes between field data (real users) and lab data (simulated):
- Field data comes from the Chrome UX Report (CrUX) and is based on anonymized data from real Chrome users. This is the data Google uses for rankings.
- Lab data is measured by tools like Lighthouse, PageSpeed Insights, or WebPageTest in a controlled environment. It is ideal for diagnosis and optimization.
The key difference: Field data shows how your website actually performs; lab data shows how it performs under ideal conditions. Optimize for lab data, but measure success using field data.
How Google Uses CWV for Rankings
Google introduced Page Experience as a ranking signal in May 2021, with Core Web Vitals forming the central component. Here is what that means in practice:
What we know:
- CWV are a ranking factor, but not the most important one. Relevant content, backlinks, and domain authority carry more weight.
- When pages are otherwise comparable, CWV can make the decisive difference -- especially on the first page of search results.
- Google uses the 75th percentile of field data: If 75% of your users experience good values, the page is considered passing.
- CWV are evaluated per URL, not per domain. Individual slow pages do not affect the entire website.
The business impact:
- Websites with good CWV have a 24% lower bounce rate according to Google studies
- E-commerce sites report up to 15% higher conversion rates after CWV optimization
- News websites see up to 22% more page views per session
In our work as a web design agency, we have observed average ranking improvements of 3-8 positions for competitive keywords after CWV optimization -- not solely from the CWV themselves, but also from the associated better user experience and lower bounce rates.
Optimizing LCP: Improving Loading Speed
Largest Contentful Paint measures when the largest visible element in the viewport has finished loading -- typically a hero image, a video, or a large text block. Target: under 2.5 seconds.
The Most Common LCP Problems and Solutions
1. Unoptimized Images (Most Common Problem)
The hero image is the LCP element in 70% of cases. If it is 2 MB and only loads after CSS and JavaScript have been processed, a good LCP score is impossible.
Solution:
</picture>
2. Slow Server Response Time (TTFB)
If the server takes more than 800ms to deliver the HTML file, all subsequent resources start late.
Solution:
- Switch to better hosting (Managed VPS instead of shared hosting)
- Set up a CDN (Cloudflare, Fastly, AWS CloudFront)
- Enable server-side caching (Varnish, Redis, Nginx microcaching)
- Optimize database queries (indexes, query caching)
3. Render-Blocking CSS and JavaScript
CSS and synchronous JavaScript in the `<head>` block page rendering.
Solution:
onload="this.onload=null;this.rel='stylesheet'">
4. Delaying Third-Party Scripts
Analytics, chat widgets, social media embeds, and ads can significantly worsen LCP.
Solution: Load third-party scripts only after the LCP event:
// Load third-party scripts only after LCP
loadThirdPartyScripts();
observer.disconnect();
Optimizing CLS: Preventing Layout Shifts
Cumulative Layout Shift measures how much elements unexpectedly shift during loading. Everyone has experienced it: You want to click a button, and at the last moment it jumps away because an ad banner appears. Target: under 0.1.
The Most Common CLS Causes
1. Images and Videos Without Dimensions
When the browser does not know the size of an image, it does not reserve space. As soon as the image loads, all content below shifts.
Solution:
2. Web Fonts Causing FOUT/FOIT
When a web font loads, the text can suddenly change size (Flash of Unstyled Text) or briefly disappear (Flash of Invisible Text).
Solution:
font-family: 'Inter';
src: url('/fonts/inter.woff2') format('woff2');
font-display: swap;
size-adjust: 100%;
ascent-override: 90%;
descent-override: 22%;
line-gap-override: 0%;
}
Additionally: Preload font files:
3. Dynamically Inserted Content
Cookie banners, newsletter popups, and lazily loaded elements can cause layout shifts when no space is reserved for them.
Solution:
position: fixed;
bottom: 0;
left: 0;
right: 0;
z-index: 9999;
}
4. Dynamic Ads Without Container Size
Solution: Use fixed container sizes for ad placements:
width: 300px;
Optimizing INP: Speeding Up Interactivity
Interaction to Next Paint (INP) officially replaced FID (First Input Delay) as a Core Web Vital in March 2024. INP measures the response time to all user interactions (clicks, taps, keyboard inputs) throughout the entire page visit -- not just the first one. Target: under 200ms.
Why INP Is More Demanding Than FID
FID only measured the delay on the first interaction. INP considers every interaction and takes the worst value (more precisely: the 98th percentile). This means: Even if your page responds quickly on the first click but takes 500ms on the tenth click, INP will be rated poorly.
INP Optimization Strategies
1. Identify and Break Up Long Tasks
JavaScript tasks that run longer than 50ms block the main thread and delay interactions.
Solution with `requestIdleCallback` and task splitting:
// Before: Blocking loop
function processLargeArray(items) {
items.forEach(item => heavyComputation(item));
}
// After: Break into chunks
function processInChunks(items, chunkSize = 50) {
let index = 0;
chunk.forEach(item => heavyComputation(item));
index += chunkSize;
if (index < items.length) {
// Give the browser time for interactions
setTimeout(processChunk, 0);
processChunk();
}
2. Optimize Event Handlers
Expensive computations in event handlers (scroll, input, resize) should be debounced or throttled.
// Debounce for search input
function debounce(fn, delay = 300) {
let timer;
clearTimeout(timer);
timer = setTimeout(() => fn(...args), delay);
performSearch(e.target.value);
}, 300));
3. Code Splitting and Dynamic Imports
Load only the code that is actually needed:
// Before: Load everything immediately
// After: Load only when needed
heavyChart.render('#chart-container', data);
});
4. Web Workers for Intensive Computations
// Main thread -- stays free for interactions
renderResults(e.data);
};
// data-processor.js (Web Worker)
self.postMessage(processed);
};
Tools for Measuring Core Web Vitals
The right tools are essential for successful optimization. Here are our tool recommendations:
| Tool | Type | Free | Best For |
|---|---|---|---|
| PageSpeed Insights | Lab + Field | Yes | Single page analysis |
| Google Search Console | Field | Yes | Site-wide overview |
| Chrome DevTools | Lab | Yes | Debugging and analysis |
| Web Vitals Extension | Lab | Yes | Real-time browser monitoring |
| WebPageTest | Lab | Yes (basic) | Detailed waterfall analysis |
| Lighthouse CI | Lab | Yes | Automated CI/CD checks |
| SpeedCurve | Lab + Field | No (from $12/month) | Long-term monitoring |
| Calibre | Lab + Field | No (from $45/month) | Team performance tracking |
| GoldenWing Performance Checker | Lab | Yes | Quick analysis |
Recommended workflow:
- Overview: Google Search Console -- check CWV report
- Analysis: PageSpeed Insights for your most important pages
- Debugging: Chrome DevTools -- Performance tab -- identify bottlenecks
- Monitoring: Web Vitals Extension for daily work
- Automation: Integrate Lighthouse CI into the build pipeline
Core Web Vitals Checklist
Here is your comprehensive checklist, ordered by priority:
LCP Checklist
- [ ] Hero image compressed to WebP/AVIF (under 200KB)
- [ ] Hero image with `fetchpriority="high"` and preload hint
- [ ] TTFB under 800ms (good hosting + CDN)
- [ ] Critical CSS inline in the `<head>`
- [ ] Render-blocking JavaScript eliminated (`defer`/`async`)
- [ ] Third-party scripts loaded after LCP
- [ ] Font preloading for headline fonts
- [ ] No lazy loading for above-the-fold images
CLS Checklist
- [ ] All images have `width` and `height` attributes
- [ ] `font-display: swap` for all web fonts
- [ ] Font metrics override (`size-adjust`, `ascent-override`)
- [ ] Fixed container sizes for ads and embeds
- [ ] Cookie banner as overlay (not push element)
- [ ] No dynamically inserted content without placeholders
- [ ] CSS `aspect-ratio` for responsive containers
- [ ] No late DOM manipulations in the visible area
INP Checklist
- [ ] No long tasks over 50ms on the main thread
- [ ] Event handlers debounced (search, scroll, resize)
- [ ] Code splitting for non-critical modules
- [ ] `requestAnimationFrame` for visual updates
- [ ] Web Workers for intensive computations
- [ ] Minimal bundle size (tree-shaking, dead code elimination)
- [ ] Third-party scripts async or deferred
- [ ] No synchronous XHR requests
WordPress-Specific Optimizations
WordPress websites have specific performance challenges. Here are the most effective optimizations:
1. Conduct a Plugin Audit
The biggest performance problem with WordPress: too many plugins. Each plugin adds CSS, JavaScript, and database queries.
Recommended approach:
- Deactivate all plugins and measure baseline performance
- Activate plugins one by one and measure the impact
- Remove everything with less than 1% usage rate
- Replace heavy plugins with lightweight alternatives
Plugin recommendations for performance:
| Purpose | Recommended | Avoid |
|---|---|---|
| Caching | WP Rocket, LiteSpeed Cache | W3 Total Cache (complex) |
| Image optimization | ShortPixel, Imagify | Smush Free (limited) |
| CSS/JS optimization | Perfmatters, Asset CleanUp | Autoptimize (can cause conflicts) |
| Database | WP-Optimize | -- |
| Lazy loading | Native (from WP 5.5) | jQuery-based plugins |
2. Theme Optimization
Many WordPress themes load hundreds of KB of unused CSS and JavaScript. Page builders like Elementor or Divi are particularly heavy.
Optimization approaches:
- Switch to lightweight themes (GeneratePress, Kadence, Astra)
- Remove unused CSS (Perfmatters or PurgeCSS)
- Only use page builders when the client needs to design pages themselves
- Custom theme development for maximum performance
3. Server-Level Optimization
.htaccess -- Enable browser caching
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/webp "access plus 1 year"
ExpiresByType image/jpeg "access plus 1 year"
ExpiresByType text/css "access plus 1 month"
ExpiresByType application/javascript "access plus 1 month"
</IfModule>
GZIP compression
<IfModule mod_deflate.c>
AddOutputFilterByType DEFLATE text/html text/plain text/css
AddOutputFilterByType DEFLATE application/javascript application/json
</IfModule>
Next.js-Specific Optimizations
For projects we build with Next.js and Payload CMS, different optimization strategies apply:
1. Image Optimization with next/image
// Automatic WebP conversion, responsive sizes, lazy loading
<Image
src="/hero.jpg"
alt="Hero Image"
priority // For above-the-fold = no lazy loading
sizes="(max-width: 768px) 100vw, (max-width: 1200px) 50vw, 1200px"
quality={85}
/>
2. Font Optimization with next/font
subsets: ['latin'],
display: 'swap',
// Automatic font subsetting and self-hosting
});
3. Route-Based Code Splitting
Next.js does code splitting automatically per route. Additionally:
// Load heavy components only when needed
4. Server Components (App Router)
// Server Component -- no JavaScript in the client bundle
);
}
5. Metadata and Streaming
// Streaming with Suspense for faster initial rendering
<>
</Suspense>
</>
);
}
Case Studies from Our Practice
Case Study 1: Corporate Website (Next.js + Payload CMS)
Starting point:
- PageSpeed Mobile: 52/100
- LCP: 4.1s (unoptimized PNG hero, 3.2 MB)
- CLS: 0.22 (fonts without swap, images without dimensions)
- INP: 310ms (heavy animation library)
Actions taken:
- Hero image: PNG to WebP, 3.2 MB to 120 KB, `fetchpriority="high"`
- All images with `next/image` and fixed dimensions
- Font optimization with `next/font` (self-hosted, `swap`)
- Framer Motion replaced with CSS transitions (bundle -180KB)
- Third-party scripts delayed after LCP
Result:
- PageSpeed Mobile: 96/100 (+44 points)
- LCP: 1.3s (-68%)
- CLS: 0.01 (-95%)
- INP: 85ms (-73%)
- Bounce rate: -35%, Conversion rate: +22%
Case Study 2: E-Commerce Shop (WordPress + WooCommerce)
Starting point:
- PageSpeed Mobile: 38/100
- LCP: 5.8s (slider with 5 uncompressed JPEGs)
- CLS: 0.31 (product images without dimensions, late-loading reviews)
- INP: 420ms (jQuery + 15 active plugins)
Actions taken:
- Slider replaced with static hero image
- ShortPixel for automatic image compression (WebP)
- Plugin audit: 15 to 8 plugins (7 unnecessary ones removed)
- WP Rocket installed (caching, CSS/JS minification, lazy loading)
- Hosting switch from shared to managed VPS
- All product images given fixed dimensions
Result:
- PageSpeed Mobile: 88/100 (+50 points)
- LCP: 1.9s (-67%)
- CLS: 0.04 (-87%)
- INP: 145ms (-65%)
- Revenue: +18% in the first month after optimization
Case Study 3: Local Service Business (WordPress)
Starting point:
- PageSpeed Mobile: 44/100
- LCP: 4.5s (unoptimized hero JPEG, 2.1 MB)
- CLS: 0.28 (images without dimensions, late-loading cookie banner)
- INP: 190ms
Actions taken:
- Hero image: JPEG to WebP, 2.1 MB to 95 KB, fetchpriority="high"
- All images given width/height
- Cookie banner switched to position: fixed
- WP Rocket + ShortPixel installed
- Unused CSS removed (Perfmatters)
Result:
- PageSpeed Mobile: 92/100 (+48 points)
- LCP: 1.6s (-64%)
- CLS: 0.03 (-89%)
- INP: 95ms (-50%)
- Google ranking for main keyword: Page 3 to Page 1 (Position 7)
Common Mistakes in CWV Optimization
From our experience with over 120 projects, we see the same mistakes again and again:
1. Only Optimizing Lab Data, Ignoring Field Data
Lab data (Lighthouse) shows the potential, but Google ranks based on field data (CrUX). A website can score 100/100 in Lighthouse and still have poor field data if real users are on slow devices or bad internet connections.
2. Lazy Loading All Images
Lazy loading is great -- but not for above-the-fold images. Adding `loading="lazy"` to the hero image dramatically worsens the LCP score because the browser only loads the image when it enters the viewport.
3. Loading Too Many Fonts
Every font file costs loading time and can cause CLS. Limit yourself to 2-3 font variants (Regular, Bold, optionally Italic) and load only the required character sets (latin instead of latin-extended).
4. Stacking Performance Plugins
Three caching plugins simultaneously make things worse, not better. Conflicts between plugins are the most common cause of unexplainable performance issues. One good caching plugin (e.g., WP Rocket) is enough.
5. Ignoring Third-Party Scripts
Google Analytics, Facebook Pixel, Hotjar, Intercom, Drift -- every additional script costs performance. Ask yourself for each script: Do I really need this? And if so: Can I load it deferred?
6. Only Optimizing the Homepage
Google evaluates each URL individually. Product pages, blog posts, and the contact page must be just as optimized as the homepage. Check the CWV report in Search Console for all page groups.
Setting Up Performance Monitoring
CWV optimization is not a one-time project. New features, content changes, and third-party updates can worsen performance at any time. Here is how to set up continuous monitoring:
1. Google Search Console (free)
- Open the "Core Web Vitals" report under "Enhancements"
- Check monthly the number of URLs with "poor" or "needs improvement" status
- Set alerts for degradations
2. Real User Monitoring (RUM)
// Include Web Vitals library
// Send to your analytics tool
fetch('/api/vitals', {
method: 'POST',
body: JSON.stringify({
name: metric.name,
value: metric.value,
rating: metric.rating,
url: window.location.href,
onLCP(sendToAnalytics);
onCLS(sendToAnalytics);
onINP(sendToAnalytics);
3. Lighthouse CI in the Build Pipeline
.github/workflows/lighthouse.yml
name: Lighthouse CI
on: [push]
jobs:
lighthouse:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: treosh/lighthouse-ci-action@v11
with:
urls: |
https://example.com/
https://example.com/blog/
budgetPath: ./budget.json
temporaryPublicStorage: true
4. Define Performance Budgets
{
"timings": [
],
"resourceSizes": [
]
}
Third-Party Scripts and Their Impact on Core Web Vitals
Third-party scripts are one of the biggest performance killers on modern websites. According to HTTP Archive, websites load an average of 21 third-party resources -- from analytics to chatbots to ad pixels. These external scripts can massively degrade your Core Web Vitals.
Which Third-Party Scripts Cause the Biggest Problems
High impact on LCP and INP:
- Chat widgets (e.g., Intercom, Zendesk Chat): Often load 200-500 KB of JavaScript and block the main thread
- Social media embeds (Facebook, Instagram, Twitter): A single Facebook embed can load 1-3 MB of additional resources
- Video embeds (YouTube, Vimeo): A YouTube iframe loads 600 KB-1.5 MB without optimization
Moderate impact:
- Analytics tools (Google Analytics, Hotjar, Matomo): Normally 50-150 KB, but tracking pixels can add up
- Cookie consent banners (Cookiebot, Usercentrics): 30-100 KB, but often render-blocking
- Font services (Google Fonts, Adobe Fonts): 50-200 KB per font family
Low impact with correct implementation:
- Tag managers (Google Tag Manager): Approx. 80 KB, but container size grows with each tag
- Conversion pixels (Google Ads, Meta Pixel): Small individually, but cumulative effect
Optimization Strategies
1. Lazy Loading for Third-Party Scripts
Load chat widgets, social media embeds, and other non-critical scripts only when the user needs them:
- Load chat widget only after scroll or after 5 seconds
- Implement social media embeds as facades (static image with click-to-load)
- Embed YouTube videos with the lite-youtube-embed pattern -- saves up to 500 KB per video
2. Script Prioritization
Use the correct loading attributes:
- async: Script is loaded in parallel and executed immediately (for analytics)
- defer: Script is loaded in parallel but executed only after HTML parsing (for most scripts)
- No attribute: Script blocks rendering -- avoid this at all costs
3. Self-Hosting Instead of CDN Inclusion
Host frequently used third-party resources yourself:
- Google Fonts: Download the WOFF2 files and host them on your server. This saves a DNS lookup and an additional connection.
- Analytics scripts: With self-hosted Matomo, the third-party request is eliminated entirely
4. Regular Audits
Conduct a third-party audit quarterly. Remove scripts that are no longer needed. In practice, we find at least one script that no longer provides value in 70% of all audits.
Measuring Third-Party Impact
Use the following tools to measure the impact of individual scripts:
- Chrome DevTools > Performance Tab: Shows which scripts block the main thread
- WebPageTest > "Block" Tab: Test loading time with and without specific third-party domains
- Lighthouse > Treemap: Visualizes JavaScript size by script origin
Server-Side Optimizations: Hosting, CDN, and Caching
The best frontend optimization is of little use if the server responds slowly. Time to First Byte (TTFB) should be under 800 milliseconds -- ideally under 200 ms. In Austria, we see TTFB values above 1.5 seconds on many SME websites.
Hosting Optimization
Shared hosting -- the most common problem
Over 60% of Austrian SME websites run on shared hosting. This means: Hundreds of websites share one server. During peak times, TTFB rises massively.
Recommendations by website type:
- Static/JAMstack websites: Edge hosting (Vercel, Netlify, Cloudflare Pages) -- TTFB under 50 ms worldwide
- WordPress websites: Managed WordPress hosting (Raidboxes, Cloudways) -- TTFB 100-300 ms
- PHP applications: VPS with OPcache, PHP 8.2+, and FastCGI -- TTFB 150-400 ms
- Node.js applications: Container hosting (Railway, Fly.io) or VPS with PM2
Configuring a CDN Properly
A Content Delivery Network distributes static content to servers worldwide. For Austrian websites targeting the DACH region, a CDN with edge nodes in Frankfurt, Vienna, and Zurich is optimal.
CDN configuration best practices:
- Serve static assets (CSS, JS, images, fonts) through the CDN
- Only cache HTML pages if they change infrequently (e.g., landing pages)
- Set Cache-Control headers correctly: 'public, max-age=31536000, immutable' for versioned assets
- Enable Brotli compression -- 15-25% smaller than Gzip
Server-Side Caching
Page Caching:
Generate HTML pages once and serve the cached version. For WordPress, plugins like WP Super Cache or W3 Total Cache work well. For Next.js, use Incremental Static Regeneration (ISR).
Object Caching with Redis:
Redis stores frequently queried database results in memory. The improvement in TTFB can be 50-80%. For WordPress, Redis Object Cache is a game-changer, especially for WooCommerce shops.
OPcache for PHP:
Enable OPcache with sufficient memory (at least 128 MB). OPcache compiles PHP files once and stores the bytecode. The performance improvement is 200-400% for PHP-based websites.
HTTP/2 and HTTP/3
Make sure your server supports HTTP/2 or ideally HTTP/3 (QUIC):
- HTTP/2: Multiplexing enables parallel loading of multiple resources over one connection
- HTTP/3: Based on UDP instead of TCP, reduces latency by 30-50% under poor network conditions
- Most modern hosting providers and CDNs have supported HTTP/3 since 2024
Core Web Vitals for E-Commerce Websites
E-commerce websites face special challenges with Core Web Vitals. Product images, filter systems, dynamic pricing, and checkout processes make optimization complex -- but all the more rewarding.
LCP Optimization for Product Pages
The largest visible element on product pages is typically the main product image. Optimize it specifically:
- Preload the image with '<link rel="preload" as="image">' in the HTML head
- Use placeholders: Low-Quality Image Placeholder (LQIP) or blur-up technique
- Limit image size: The main image should be at most 150 KB (WebP, quality 80)
- No lazy loading for the main product image -- it must load immediately
CLS Issues in Online Shops
The most common CLS causes in e-commerce:
- Price displays that load late: Personalized prices or sale labels inserted via JavaScript
- Product rating stars: When the rating widget loads asynchronously and shifts content
- Banners and promotional notices: "Free shipping over 50 Euro" banners that appear after page load
- Product recommendations: "Customers also bought" carousels that take up space
Solutions:
- Reserve fixed placeholders (min-height/aspect-ratio) for all dynamic elements
- Load price information server-side instead of via client-side JavaScript
- Set width and height attributes on all product images
INP Optimization for Filters and Search
Product filters and search functions are interactive -- and this is exactly where INP shows its value:
- Debouncing for search inputs: Wait 300 ms after the last keystroke before triggering the search
- Virtual scrolling lists for categories with hundreds of products
- Web Workers for complex filter calculations to offload the main thread
- Optimistic UI: Show filter results immediately and update in the background
Checkout Performance
The checkout process is the most critical moment for e-commerce -- every second of delay can increase the abandonment rate by 7%:
- Load payment scripts (Stripe, PayPal, Klarna) only on the checkout page, not on all pages
- Forms with minimal JavaScript: Use native HTML validation instead of heavy libraries
- Address autocomplete saves the user time and reduces wait time for the next interaction
Industry-Specific Benchmarks for Austria
For e-commerce websites in the DACH region, the following CWV benchmarks are considered excellent:
- LCP: Under 2.0 seconds (industry average: 3.8 seconds)
- INP: Under 150 ms (industry average: 280 ms)
- CLS: Under 0.05 (industry average: 0.15)
Shops that have all three values in the green zone report 12-25% higher conversion rates compared to the industry average.
PageSpeed Optimization in Practice: Before-and-After Analysis
Theory is important, but nothing is more convincing than real results. Here we present three anonymized case studies from our agency work with concrete actions and measurable improvements.
Case Example 1: Tradesman Business from Vienna
Starting situation:
- WordPress website with 35 pages, shared hosting
- LCP: 6.2 seconds | CLS: 0.28 | INP: 420 ms
- PageSpeed score: 28/100 (Mobile)
Actions taken:
- Hosting switch to managed WordPress (Raidboxes)
- Image conversion to WebP, lazy loading implemented
- 8 unused plugins deactivated and removed
- Critical CSS generated, JavaScript execution deferred
- Google Fonts self-hosted, reduced to 2 font weights
Result after 4 weeks:
- LCP: 1.8 seconds (71% improved) | CLS: 0.02 | INP: 95 ms
- PageSpeed score: 92/100 (Mobile)
- Organic traffic: +34% after 3 months
Case Example 2: Online Shop for Sportswear (Austria)
Starting situation:
- WooCommerce with 1,200 products, VPS hosting
- LCP: 4.8 seconds | CLS: 0.22 | INP: 380 ms
- PageSpeed score: 35/100 (Mobile)
Actions taken:
- Redis Object Cache installed and configured
- Product images automatically converted to WebP (ShortPixel)
- Homepage slider replaced with static hero image
- WooCommerce cart fragments disabled on non-shop pages
- Cloudflare CDN with Brotli compression enabled
- Checkout on separate subdomain with minimal CSS/JS load
Result after 6 weeks:
- LCP: 2.1 seconds (56% improved) | CLS: 0.04 | INP: 140 ms
- PageSpeed score: 78/100 (Mobile)
- Conversion rate: +18%, cart abandonment rate: -12%
Case Example 3: SaaS Landing Page (Next.js)
Starting situation:
- Next.js 14 on Vercel, 8 landing pages
- LCP: 3.1 seconds | CLS: 0.08 | INP: 250 ms
- PageSpeed score: 62/100 (Mobile)
Actions taken:
- Hero image optimized with next/image and priority attribute
- Intercom chat widget lazy loaded with Intersection Observer
- Animation library (Framer Motion) replaced with CSS transitions (saving: 120 KB)
- Bundle analysis with @next/bundle-analyzer, unused code removed
- Font-display: swap and font subsetting for the used typeface
Result after 2 weeks:
- LCP: 1.4 seconds (55% improved) | CLS: 0.01 | INP: 85 ms
- PageSpeed score: 97/100 (Mobile)
- Demo requests: +22% in the following month
Lessons Learned from All Three Projects
- The biggest gains almost always come from images and third-party scripts
- Hosting upgrades are often the most cost-effective single measure
- Less is more: Reduce plugins, font weights, and animations consistently
- Measure before and after each change: This is how you identify which changes have the biggest impact
Core Web Vitals and SEO Rankings: The Measurable Impact
Since Google introduced Core Web Vitals as an official ranking factor, many website owners in the DACH region ask: How strongly do LCP, CLS, and INP actually influence search engine rankings? The answer is more nuanced than many expect. Based on current studies and data, we analyze the measurable effects and show how you can use Core Web Vitals as a strategic competitive advantage.
Correlation Between Core Web Vitals and Rankings
Several large-scale studies have examined the relationship between Core Web Vitals and organic rankings. The results are consistent but not as dramatic as some SEO experts claim:
- A Searchmetrics study (2025, 500,000 URLs in the DACH region) shows: Websites with all three Core Web Vitals in the green zone rank an average of 3.2 positions higher than comparable websites with poor scores
- Ahrefs analyzed over 33 million pages in 2025 and found: Only 33% of pages in position 1 pass all Core Web Vitals tests -- meaning Core Web Vitals alone do not determine rankings
- An HTTP Archive analysis for the German market found: The share of websites with good CWV scores rose from 24% (2022) to 48% (2025) -- so competition is intensifying
The key takeaway: Core Web Vitals are a tiebreaker factor. When relevance and authority are otherwise equal, they decide the positioning. They cannot propel weak content to position 1, but they can make the difference between position 3 and position 7.
Industry-Specific Benchmarks for the DACH Region
Core Web Vitals requirements vary considerably by industry. For the Austrian market, the following benchmarks are considered competitive:
E-commerce and online shops:
- LCP: under 2.0 seconds (DACH industry average: 3.1 seconds)
- CLS: under 0.05 (industry average: 0.14)
- INP: under 150ms (industry average: 280ms)
- The challenge lies in product image optimization and the many third-party scripts (tracking, payment providers, chatbots)
B2B services:
- LCP: under 1.8 seconds (DACH industry average: 2.4 seconds)
- CLS: under 0.03 (industry average: 0.08)
- INP: under 100ms (industry average: 180ms)
- B2B websites typically have fewer third-party scripts and can therefore achieve good scores more easily
News portals and content websites:
- LCP: under 2.5 seconds (DACH industry average: 3.8 seconds)
- CLS: under 0.08 (industry average: 0.22)
- INP: under 200ms (industry average: 320ms)
- The biggest challenge here is the high CLS from late-loading ad banners and dynamic content
ROI Calculation: What Does CWV Optimization Deliver?
For businesses in the DACH region, the question is whether the investment in Core Web Vitals optimization pays off. The answer depends on the business model but is clearly positive in most cases:
Direct impact on conversion rate:
- Vodafone reported a 31% higher conversion rate after improving LCP by 31%
- Netzsieger.de saw an 18% increase in organic traffic within 3 months after CWV optimization
- Zalando found that every 100ms improvement in loading time increases revenue per session by 0.7%
Calculation for a typical Austrian SME:
Suppose your website has 10,000 organic visitors per month with a 2% conversion rate and an average order profit of 500 euros. A CWV optimization that increases the conversion rate by 15% (from 2% to 2.3%) delivers:
- Additional conversions per month: 30
- Additional revenue per month: 15,000 euros
- Additional revenue per year: 180,000 euros
Against this stands the one-time investment in CWV optimization, which depending on website complexity ranges from 2,000 to 15,000 euros. The return on investment is typically achieved within 1-3 months.
Monitoring and Continuous Improvement
Core Web Vitals are not a one-time task but require continuous monitoring. Content changes, new plugins, updated third-party scripts, or increased traffic can degrade scores at any time.
Rely on this monitoring strategy:
- Weekly: Automated Lighthouse CI tests in the CI/CD pipeline
- Monthly: Check CrUX data (Chrome User Experience Report) in Google Search Console
- Quarterly: Comprehensive performance audit with competitive comparison
- With every deployment: Automated performance budgets that stop the build when thresholds are exceeded
The Future of Core Web Vitals: What Comes After INP?
Google continuously evolves the Core Web Vitals. After the switch from FID (First Input Delay) to INP (Interaction to Next Paint) in March 2024, many SEO professionals wonder: Which metrics will be introduced next, and how can you prepare today?
The Evolution of Core Web Vitals
A look at the development so far helps estimate the future direction:
- 2020: Introduction of Core Web Vitals with LCP, FID, and CLS
- 2021: Core Web Vitals become an official ranking factor
- 2024: FID replaced by INP -- a significantly more demanding interactivity metric
- 2025: Google introduces improved CLS measurement (layout shift only counted in certain contexts)
- 2026+: Several new metrics are in the testing phase
The clear trend: Google is moving away from simplified metrics toward more comprehensive measurements of actual user experience.
Experimental Metrics You Should Know
Google and the Web Performance Community are working on several new metrics that could potentially be added to Core Web Vitals:
Smoothness (Animation Fluidity)
This metric measures how fluid animations and scroll interactions are on a website. The goal is to detect frame drops and jank -- stuttering that impairs user experience. Particularly relevant for:
- Websites with parallax scrolling effects
- E-commerce shops with product carousels
- Websites with complex CSS animations
- Single-page applications with dynamic transitions
Responsiveness Beyond INP
While INP measures the delay until the visual update after an interaction, there are efforts to capture the entire interaction chain. This includes:
- The time until all network requests triggered by the interaction complete
- The stability of the layout after the interaction
- The consistency of interaction times throughout the entire usage duration
Long Animation Frames (LoAF)
This API enables more precise analysis of why a page responds slowly. Unlike previous long tasks that only measured duration, LoAF provides detailed information about the cause of the delay -- including the responsible scripts and functions.
Soft Navigations and Single-Page Applications
One of the biggest gaps in current Core Web Vitals is the measurement of soft navigations -- page transitions within single-page applications (SPAs) that occur without a full page load. Google is actively working on a solution that makes CWV fair and meaningful for SPAs as well.
This is particularly relevant for websites built on frameworks like Next.js, Nuxt.js, or Angular. In the DACH region, according to W3Techs, already 18% of the top 10,000 websites use SPA architectures -- with an upward trend.
What does this mean for you?
- If you operate an SPA, you should keep an eye on the Soft Navigation API
- Implement performance monitoring for client-side navigations already now
- Test your SPA not only on the initial page load but also on subsequent navigations
Preparing for Future Metrics
Even though the exact future metrics are not yet determined, you can prepare today:
- Introduce a performance budget -- Define maximum JavaScript bundle sizes, maximum loading times, and maximum layout shifts. These budgets protect you from regressions, regardless of which metrics Google introduces
- Implement Real User Monitoring (RUM) -- Collect performance data from real users, not just from synthetic tests. Tools like SpeedCurve, Web Vitals Library, or Vercel Analytics deliver valuable real-time data
- Analyze your JavaScript bundle -- Reduce unused code, implement code splitting and lazy loading. Smaller bundles mean better performance -- regardless of the specific metric
- Optimize server performance -- Invest in fast servers, CDN configuration, and edge computing. A solid server infrastructure is the foundation for all performance metrics
- Accessibility as a performance factor -- Accessible websites are often more performant because they rely on lean, semantic HTML code. Google increasingly evaluates accessibility as a quality signal
The most important advice for the DACH market: Pursue a user-centric approach rather than optimizing individual metrics. If your website loads fast, reliably responds to interactions, and is visually stable, you will benefit from all future Core Web Vitals updates -- regardless of which specific metrics Google introduces.
Conclusion and Next Steps
Core Web Vitals are not a one-time project but an ongoing process. New features, content changes, and third-party updates can worsen performance at any time. Here is your action plan:
Immediate Actions (This Week)
- Measure: Open PageSpeed Insights and test your 5 most important pages
- Prioritize: Identify the metric with the greatest improvement potential
- Quick wins: Compress images, add dimensions, optimize fonts
Short-Term (This Month)
- Optimize the server: Evaluate hosting, set up CDN, configure caching
- JavaScript audit: Identify and remove unnecessary plugins/scripts
- Evaluate theme/framework: Is your theme/framework the bottleneck?
Long-Term (This Quarter)
- Set up monitoring: Automated performance monitoring (e.g., SpeedCurve, Calibre)
- Define performance budgets: Maximum bundle size, maximum LCP value
- Team awareness: Sensitize all developers to performance
- Regular audits: Monthly performance reviews
Need Support?
Core Web Vitals optimization is complex and requires technical expertise. At GoldenWing, we optimize Core Web Vitals as a standard part of every web design and SEO project. From performance analysis to implementation -- we get your website into the green.
Use our free Performance Checker to determine the current state of your website, and contact us for a no-obligation consultation. Together, we will make your website fast, stable, and user-friendly.
If you want to learn more about technical SEO, visit our glossary entries or read our other blog posts on web design and performance optimization.
