Short answer: go to PageSpeed Insights, enter your website address and stay on the Mobile tab. Look at the top section first. If its Core Web Vitals assessment has passed, most real visitors had a good experience. If it failed, the three numbers under it show where the problem is.
Why it matters
Many people look you up on their phone, and a slow or jumpy page makes a business look less established. In mid-2025, only 48% of mobile websites worldwide had good Core Web Vitals, Google’s measures of loading, responsiveness and visual stability (HTTP Archive, Web Almanac 2025).
How to test your site
- Open pagespeed.web.dev.
- Paste your homepage address and press Analyze.
- Make sure the Mobile tab is selected.
- Read the top section first. It shows what real Chrome users experienced over the previous 28 days.
- The score out of 100 further down is a lab test on a simulated phone. It’s useful for finding problems, but the Core Web Vitals assessment comes from the real-visitor data, not this score.
What the three numbers mean
- LCP (Largest Contentful Paint): how long the main content takes to appear. Good is 2.5 seconds or less.
- INP (Interaction to Next Paint): how quickly the page responds when someone taps. Good is 200 milliseconds or less.
- CLS (Cumulative Layout Shift): how much the page jumps around while it loads. Good is 0.1 or less.
The assessment passes when the 75th percentile of page loads is good on all three, so at least three in four page loads need to meet each one (Google, About PageSpeed Insights; Google, Web Vitals).
If there’s no real-visitor data
Smaller sites often don’t get enough Chrome visitors. PageSpeed Insights then shows data for your whole site if it has some, or no real-visitor data at all. In that case, use the lab section lower down. It measures LCP and CLS on a simulated phone, and uses Total Blocking Time in place of INP. Run the test two or three times, because lab results change a little between runs.
Common causes on small business sites
- Large photos uploaded straight from a phone or camera
- Sliders, pop-ups and chat widgets loading on every page
- Page builders and plugins that load far more code than the page needs
- Fonts and scripts pulled in from several other websites
- Slow, overloaded hosting
What to do next
Start with the biggest images, which are often the biggest cause and the easiest to fix. If most of the problem comes from the page builder or theme, a rebuild can work out cheaper than patching it again and again.
Where ShreeNova fits
We build static websites that send finished pages to the browser, with no heavy page builder, and we test every site with PageSpeed Insights before launch. Request a free homepage mockup, or see what’s included in each package.