Technical
How to improve your Core Web Vitals
Google watches how quickly your page becomes usable and how much it shifts around as it loads, and it feeds that into ranking. The more direct problem is simpler: a slow page loses readers before they see anything at all.
What it is
Core Web Vitals are three measurements. LCP (Largest Contentful Paint) is how long until the main content appears. CLS (Cumulative Layout Shift) is how much the page jumps while loading. INP (Interaction to Next Paint) is how quickly it responds to a tap or click.
Why it costs you
They are a confirmed ranking signal, small but real, and more importantly they track what a visitor feels. A slow LCP means people leave before your page paints. A high CLS is the page that moves just as you go to tap, so you hit the wrong thing. Google measures these from real Chrome users, so the numbers are what your actual visitors experience, not a lab guess.
How to fix it
The top three causes are almost always the same, in this order.
- Images: oversized images are the usual LCP killer. Serve them at the size they display, in a modern format (WebP/AVIF), and lazy-load anything below the fold. On WordPress a plugin like ShortPixel or the built-in lazy-load handles most of it; on Shopify, use the theme’s responsive image tags.
- Render-blocking scripts and fonts: defer non-critical JavaScript, and preload the font your headline uses so text does not flash or shift. Reserve space for anything that loads late (images, ads, embeds) with width/height attributes to stop CLS.
- Slow server or no caching: put a cache or CDN in front of the site so the HTML arrives fast. On WordPress, a caching plugin plus a CDN covers it.
How to check your site
Run the page through Google PageSpeed Insights. It shows both lab scores and the real-user field data Google actually ranks on. Search Console has a Core Web Vitals report across your whole site.
What this looks like in practice
A landing page scored a 4-second LCP from a single 3 MB hero image. Resizing and converting it to WebP dropped LCP under 2 seconds without touching anything else.
Questions people ask
- How much does this help rankings?
- On its own, a little: it is a tie-breaker more than a lever. But the reader experience it measures affects conversions directly, which is often the bigger win.
- Lab score or field data?
- Google ranks on field data (real users). Use the lab score to debug, but judge success by the field numbers in Search Console.
Does your site have this?
Check your site to see how each page scores on speed.
See also
- How to fix a missing mobile viewport tagWithout a viewport tag, a phone draws your page at desktop width and then shrinks the whole thing to fit. Text comes out too small to read, taps land on the wrong link, and Google indexes the mobile version of your site, so this is the version that counts.
- How to fix a missing character encodingThese pages do not declare a character set, so the browser guesses. When it guesses wrong, accented characters and quotation marks come out as garbage.
- How to make your pages mobile-friendlyThese pages fix their layout to a desktop width in pixels. On a phone that means horizontal scrolling and tiny text, and since Google ranks what it sees on mobile, it is the version that counts.
- How to fix content that only appears after JavaScriptMost of the text on these pages only appears after JavaScript runs. Search engines do render JavaScript, but later and less reliably, so content that is not in the HTML your server sends may never be indexed.