Core Web Vitals: What They Are and Why Your Website Might Be Failing Them

When I do a local SEO audit, page speed and Core Web Vitals come up almost every time. Not because they're the most dramatic finding — they usually aren't — but because they're a quiet drag that compounds everything else. You can have great local content, a solid Google Business Profile, and consistent reviews, and still be losing visitors before they've read a word.

Core Web Vitals are Google's formal way of measuring that experience. They're not abstract technical scores — they're measurements of three things real users feel when they land on your page.

Three numbers, one score

Google tracks three metrics under the Core Web Vitals umbrella. Each one measures a different aspect of how a page feels to use.

To pass Core Web Vitals, a page needs a "Good" rating in all three metrics for at least 75% of real visitors. That last part matters — Google uses actual user data, not just a single lab test. A page can look clean in a speed test and still fail because real-world conditions vary: slow cellular connections, older phones, traffic spikes.

Most mobile websites are currently failing

Here's the part that surprises most business owners. According to the 2025 Web Almanac, only 48% of mobile websites pass all three Core Web Vitals. That means more than half the mobile web — including many small business sites across Vancouver Island — is currently delivering a page experience Google has formally rated as substandard.

The individual metric pass rates tell a useful story. INP (interactivity) and CLS (layout stability) are areas most sites handle reasonably well. LCP — how fast the main content appears — is where most sites struggle. And since you need all three to pass, a single poor LCP score is enough to fail the whole page.

Why this matters beyond your ranking

Core Web Vitals became a confirmed Google ranking signal in 2021. The honest framing, though, is that Google describes it as a tiebreaker — relevant when content quality is otherwise equal. So you shouldn't expect a CWV fix to launch you from page three to page one. But that's not the main reason to care.

The more important impact is on the people who do find you. Page speed directly affects whether they stay, and whether they contact you. The data on this is consistent and significant.

For a local service business — a trades company in Courtenay, a spa in Qualicum Beach, a law firm in Victoria — every lost visitor is a lost enquiry. You're not running an e-commerce store with thousands of daily visitors where you can absorb a 7% conversion drop across a large base. You might get 40 relevant visitors a month. If half of them leave because the page is slow, that's a real number.

What's usually causing the problem

When I flag Core Web Vitals in a Vancouver Island SEO audit, the causes are usually one of three things:

Unoptimised images. This is the culprit in the majority of LCP failures on small business sites. A photographer sets their homepage hero image at 4,000 pixels wide and 3MB in size, because that's how it came out of their camera. The browser downloads the whole thing before it can display anything. The fix is compressing the image, resizing it to a sensible display width, and ideally converting it to WebP format. That single change often drops LCP from 6s to under 2s.

Layout shift from late-loading elements. Fonts, banner ads, chat widgets, or images without explicit dimensions declared in the HTML — these load after the initial render and push other content out of the way. The result is the jumping-text problem that makes sites feel unstable. Declaring width and height on images and reserving space for fonts in CSS eliminates most of it.

Heavy third-party scripts. This is the INP problem. A live chat widget, a Facebook Pixel, a Google Tag Manager container with fifteen tags inside it — each one runs JavaScript that competes with user interactions. The page looks loaded but responds slowly to taps and clicks because the browser is still processing scripts in the background. Auditing what's in your tag manager and removing what isn't actively used can make a noticeable difference.

How to check your own scores

You don't need any tools or accounts to get started. Go to pagespeed.web.dev, enter your homepage URL, and run the test. Google's PageSpeed Insights gives you both a lab score and real-world field data from actual Chrome users if your site has enough traffic to measure.

Run it twice — once for desktop and once for mobile. The mobile score is the one to focus on. A good desktop score with a poor mobile score is still a failure from Google's perspective, because mobile is where local search happens.

If you've already verified your site with Google Search Console, there's a Core Web Vitals report in the left-hand navigation under Experience. It shows which URLs are passing and which are failing based on real user data — more reliable than a single lab test, and it shows you exactly which pages have problems, not just the homepage.

• Run PageSpeed Insights on your homepage URL — check both mobile and desktop tabs
• Look for the "Largest Contentful Paint" number specifically — under 2.5 seconds is the target
• Any image over 500KB is worth compressing before anything else
• Check Search Console's Core Web Vitals report for a page-by-page view using real visitor data
• Note any "Poor" URLs — those are hurting your page experience score in rankings

None of this requires a developer if you're on a standard website platform. Most hosting setups have image optimisation plugins or built-in compression. The fixes are rarely glamorous, but they're usually not complicated either.

Core Web Vitals show up in almost every audit I do for a reason: they're easy to neglect (the site still works) and the cost of neglecting them is invisible until you look at the data. If you'd like a clear picture of where your site stands and what to prioritise, that's exactly what the Local Spotlight audit covers — Core Web Vitals, page speed, and a plain-English action plan for fixing what matters most.

Written by Michael Perks — Island Rank Canada, Duncan, BC. I do hands-on SEO audits for small businesses across Vancouver Island. If you've never checked your Core Web Vitals score, the contact page is a good place to start.