Back in 2020, Google launched an initiative called Web Vitals. In its own words:
"Web Vitals is an initiative by Google to provide unified guidance for quality signals that are essential to delivering a great user experience on the web."
Six years on, it's still how Google measures whether your website is pleasant to use - although one of the measurements has changed since it launched. So what does that mean for you and your website? I'll explain below.
Simply put, Core Web Vitals are a set of measurements Google uses to judge how your website performs for the people using it. Rather than drowning you in technical data, Google has boiled it down to three key areas, so anyone - business owners, marketers or developers - can see how their site is doing and where it needs to improve.
Google always said the metrics would evolve over time, and they have. In March 2024, a new measure called Interaction to Next Paint (INP) replaced First Input Delay (FID). More on that below.
LCP measures how quickly the main content of a page loads and becomes visible. To provide a good experience, it should happen within 2.5 seconds of the page starting to load. It goes without saying that a slow website will put visitors off - people want information quickly, and they won't wait around for it.
This is the one that's changed. The old measure, FID, only looked at the very first time someone interacted with a page. INP looks at every click, tap and key press during a visit, and measures how long it takes for the page to visibly respond. To provide a good experience, aim for 200 milliseconds or less (quick, I know!).
Heavy JavaScript is usually what slows this down - things like chat widgets, tracking scripts and sliders that keep the browser busy when someone's trying to use the page.
CLS measures how much the page jumps around while it loads. You've probably experienced it - you go to tap a link, an image or advert loads in above it, and you end up tapping something else entirely. Aim for a CLS of 0.1 or less.
For all three, Google looks at real visits to your site. To pass, at least three-quarters of visits need to hit the target.
Google says it highly recommends good Core Web Vitals for success in Search, and that they line up with what its ranking systems are looking to reward. But it's worth being clear about what that does and doesn't mean.
There's no single "page experience" score that bumps you up the rankings, and Google says it will always show the most relevant content, even if the page experience isn't great. So a fast website won't rank on speed alone. Where it helps is when you and a competitor are both offering something useful - a better experience can tip things in your favour. And a site that's quick and easy to use is more likely to turn visitors into customers anyway, rankings or not.
The easiest way is Google's PageSpeed Insights. Pop your web address in, hit Analyse, and after a few seconds you'll get two sets of results. It's worth knowing the difference:
The Core Web Vitals assessment at the top is based on real visits to your site from Chrome users over the last 28 days. This is the one Google actually uses.
The performance score out of 100 underneath comes from a simulated test. It's really useful for spotting problems, but it isn't the same thing as your Core Web Vitals.
For the score out of 100, 90-100 is good, 50-89 needs improvement and 0-49 is poor. 100 is the magical number all website owners dream of, but don't stress about not hitting it. As long as you're in the 90s, you can rest easy knowing your site performs well.
One thing that catches a lot of small businesses out: if your site doesn't get much traffic, PageSpeed Insights might not have enough real-world data to show a Core Web Vitals assessment at all. That's completely normal. In that case, the score out of 100 is the best guide you've got.
If you've got Google Search Console set up, its Core Web Vitals report shows how every page on your site is doing over time.
Some fixes are easy. Large images are one of the most common causes of a slow LCP, so compressing them and switching to modern formats like WebP is a good place to start. I've covered that and more in 5 tips to speed up your WordPress website.
Other fixes are more technical, like cutting back heavy JavaScript to improve INP, or reserving space for images so the layout doesn't shift as they load. That's where I come in. I obsess over these scores so you don't have to, and I do everything I can to make sure the sites I build land in that 90-100 range.
Making sure your website meets Google's Core Web Vitals isn't something you should ignore. A good experience is more likely to generate leads and turn browsers into customers. On top of that, a boost in your rankings isn't so bad either, is it?
If you'd like some help with your website's performance, get in touch or take a look at my SEO services.
01 Keep reading