Page speed and Core Web Vitals

What do LCP, INP and CLS measure?

Largest Contentful Paint is how long the biggest thing on the screen takes to appear, usually your hero photo or headline. Good is 2.5 seconds or less.

Interaction to Next Paint is how quickly the page reacts when someone taps or clicks, like opening your menu or pressing Book Now. Good is 200 milliseconds or less. INP replaced an older metric, First Input Delay, in 2024.

Cumulative Layout Shift is how much the page jumps around while it loads. You've felt it when you go to tap Call and a banner loads above it, so you tap something else. Good is 0.1 or less.

Google checks each at the 75th percentile of real visits, split by mobile and desktop. Mobile is the one to watch, since most local searches happen on a phone and Google indexes the mobile version of your site.

What slows most small business sites down?

The same few things show up again and again on plumber, dentist and law firm sites, and most of them are fixable in an afternoon without a rebuild. Start with whatever PageSpeed Insights lists first for mobile.

• Huge photos. A 6 MB phone photo used as a hero image is the most common cause of a slow LCP. Resize and compress before uploading.
• Too many plugins, widgets and tracking scripts, each adding code the phone has to run before it responds. This hurts INP.
• Images, ads and embeds with no set size, so the page jumps when they load. This hurts CLS.
• Slideshows and background videos at the top of the page.
• Cheap shared hosting that takes a second or more just to start sending the page.

How much does speed matter for ranking?

Google uses Core Web Vitals as part of its page experience signals, but it says relevance comes first. A fast page with thin content won't outrank a slower page that answers the question better. Speed matters most as a tiebreaker and for the customer: a visitor who waits on a blank screen often goes back and calls the next business.

So fix the big, cheap problems first, like oversized images and layout jumps, and don't rebuild your site to chase a perfect score.

Lab scores and real visits can disagree. PageSpeed Insights shows both: a lab test from one simulated phone, and real visitor data from Chrome users when your site has enough traffic. The real visitor data is what Google uses. A small site may not have enough visits for it, so use the lab test as a guide.

Common mistakes

• Uploading photos straight from a phone at full size.
• Testing only on a fast office computer instead of looking at mobile results.
• Chasing a perfect score with a full rebuild when resizing a few images would fix the real problem.