Mobile speed: what Google measures
Photo: Avila Ops Tecnologia
Google measures your website’s mobile speed using three numbers collected from real visitors: how long the largest element on the screen takes to appear (LCP, good up to 2.5 seconds), how long the page takes to respond to a tap (INP, good up to 200 milliseconds), and how much the content shifts while loading (CLS, good up to 0.1). These three metrics, called Core Web Vitals, appear in Search Console and contribute to page assessment alongside content.
Most visits to a small-business website come from phones, often on 4G, and a page that takes 6 seconds loses visitors before showing its phone number. Speed will not make a weak page rank higher, but it can make a good page lose to an equivalent page that loads faster. And the problem is almost always simple to fix.
What does each number measure?
LCP (Largest Contentful Paint) is the time until the largest visible block appears: usually the cover photo or large heading. If your homepage opens with a 4 MB image, LCP is poor even if everything else is perfect.
INP (Interaction to Next Paint) is the delay between a tap and the screen’s response. A page that freezes when you open its menu or tap a button has poor INP. The cause is usually too many scripts running at once: chat, pixel, map, video, cookie banner.
CLS (Cumulative Layout Shift) measures how much content moves after appearing. You try to tap “WhatsApp,” a banner loads above it, pushes everything down, and you tap an ad. That is CLS. It is caused by an image or block without reserved dimensions.
Google uses these thresholds, measured at the 75th percentile of visitors (meaning three out of four visits must fall within them):
| Metric | Good | Needs improvement | Poor |
|---|---|---|---|
| LCP | up to 2.5 s | 2.5 to 4 s | above 4 s |
| INP | up to 200 ms | 200 to 500 ms | above 500 ms |
| CLS | up to 0.1 | 0.1 to 0.25 | above 0.25 |
How do I see my numbers?
Search Console, under “Experience” > “Core Web Vitals,” divides your entire site into good, needs improvement, and poor, using real visitor data from the last 28 days. Sites with little traffic show “not enough data”; in that case, use PageSpeed Insights. The guide Search Console: the report that tells you what to fix explains how to read the dashboard.
PageSpeed Insights is a free Google tool: paste the page URL and it shows real visitor numbers when data is available, an immediate test, and a list of what is slowing things down. The test measures LCP and CLS; INP requires a real visitor’s interaction. Test the homepage and your most important service page in mobile mode.
Do not get stuck on the 0-to-100 score. It is a simulation; Google uses the three real visitor numbers for its assessment. A page scoring 60 with all three in the green is doing well.
What should you fix first?
On small-business websites, five causes explain almost everything:
- Heavy images. A phone photo is 3 to 5 MB; on a website, it should be 100 to 300 KB. Resizing to its displayed width and saving as WebP fixes most poor LCP scores. This fix brings the biggest return.
- Third-party scripts. Every chat, pixel, embedded map, and review widget is a script. Keep what you use; load the rest after the page appears.
- Slow hosting. If the server takes a second to start responding, nothing else can save it. Shared hosting at R$ 10 a month on an overseas server is a common cause. Avila Ops domain and hosting services include a server with measured response times.
- Fonts and background video. Four font families and a looping cover video are the recipe for a slow page. Use two fonts and a static image.
- Unreserved dimensions. Every image and every advertising or embed block needs its width and height defined in the code so content does not shift.
After fixes, Search Console data takes 28 days to reflect them because it uses a rolling window. PageSpeed shows results immediately.
What to do now
Test your homepage in PageSpeed Insights in mobile mode and look at the numbers. If LCP exceeds 2.5 seconds, start with images; it takes an afternoon and solves most cases. If you want a website built within these thresholds on hosting with measured performance, you can see a free prototype in 48 hours: avilaops.com/criacao-de-site-profissional or contact us on WhatsApp: wa.me/5517997811471.
Frequently asked questions
Is speed the most important factor in appearing on Google?
No. Content that answers the search matters much more. Speed breaks ties between similar pages and prevents visitors from leaving before reading. Treat it as basic maintenance rather than a strategy.
My website is fast on my phone. Why does Google say it is slow?
Because you have the site cached, good Wi-Fi, and a recent phone. Google measures your visitors as a whole (the 75th percentile, not the best case), many on 4G and simpler devices. PageSpeed simulates that condition.
Will a caching plugin solve it?
It helps with server response and part of LCP. It does not fix heavy images, excessive scripts, or CLS. Use it, but address the causes.
Turn what you learned into your next step.
Tell us about your company and what you want to improve. We can explore the right tools, integrations or custom project together.