Web Development · 6 min read
Core Web Vitals explained for business owners
By Kunal Kapoor, Founder, WES Agency Co. ·
Core Web Vitals are Google's measures of how a page feels to use: how fast the main content appears, how quickly the page responds, and whether things jump around as it loads. You don't need to be a developer to understand them, and they're worth understanding.
The three measurements
- Largest Contentful Paint (LCP): how long the main content takes to appear. Good is 2.5 seconds or less.
- Interaction to Next Paint (INP): how quickly the page responds when someone taps or clicks. Good is 200 milliseconds or less. INP replaced the older First Input Delay measure in March 2024.
- Cumulative Layout Shift (CLS): how much the layout jumps around while loading. Good is 0.1 or less.
How they're measured
Google assesses these from real visits using Chrome, at the 75th percentile, so most of your visitors need a good experience, not just the ones on fast connections. PageSpeed Insights and the Core Web Vitals report in Google Search Console both show this field data once your site has enough traffic. Lab tools like Lighthouse simulate a visit, which is useful for finding problems but isn't what Google uses to assess the site.
Do they affect rankings?
Yes, but as one signal among many. Relevance and quality still matter far more; a fast page with the wrong content won't outrank a slower page that answers the search better. Where Core Web Vitals really count is in competitive results, where several pages are similarly relevant, and in keeping visitors who would otherwise leave.
A real example from our own site
When we audited this website, the main headline on most pages took almost three seconds to count as loaded on a mobile test, even though the text was already in the page. The cause was a fade-in animation: the text started invisible and only appeared once the page's JavaScript had loaded. Around 78% of the loading time was that delay. Removing the animation from the top of each page brought that time down on every page we retested. Small design choices can have a big effect.
Common causes and fixes
- Oversized images: compress them and serve the right size for each screen
- Content hidden until scripts load: make the top of the page visible immediately
- Heavy third-party scripts such as chat widgets and trackers: load them later or remove what you don't use
- Images and embeds without reserved space: set dimensions so the layout doesn't shift
- Slow hosting: move to modern hosting served close to your visitors