Core Web Vitals: How to Speed Up Your Website and Improve Rankings
Page speed affects both rankings and conversions. We explain Core Web Vitals (LCP, CLS, INP) and the concrete steps you can take to make your site faster.
Why Speed Matters
Speed affects two things simultaneously: search rankings (Core Web Vitals are a confirmed ranking factor) and conversions (every extra second increases bounce rate). A slow site loses both customers and organic traffic — especially on mobile.
Three Key Metrics
- LCP (Largest Contentful Paint) — how quickly the main content renders. Target: under 2.5 s.
- CLS (Cumulative Layout Shift) — visual stability, so content doesn't jump around. Target: under 0.1.
- INP (Interaction to Next Paint) — how quickly the page responds to user input. Target: under 200 ms.
The Most Common Causes of a Slow Website
- Large, unoptimised images — compress them and switch to WebP/AVIF with lazy-loading.
- Too much JavaScript — defer non-critical scripts.
- Render-blocking CSS/JS in the document head.
- Slow hosting / high TTFB — consider upgrading your hosting or adding a CDN.
- Missing browser caching and compression (gzip/Brotli).
How to Measure and Fix
Run a speed test — it measures your Core Web Vitals and overall performance score and surfaces specific improvement opportunities ranked by impact. Then work through them starting with the biggest wins: usually images and JavaScript.
Frequently asked questions
Is speed really an SEO factor?
Yes. Core Web Vitals are part of Google's page experience ranking signal. When content quality is comparable between two pages, speed can be the tiebreaker.
Is it enough to optimise only for desktop?
No. Google evaluates primarily the mobile version of your site (mobile-first indexing), and the majority of web traffic now comes from mobile devices. Focus on mobile speed first.