Core Web Vitals Explained for Business Owners
You have probably heard that website speed matters, but the reports can read like a foreign language. Core Web Vitals are Google’s way of measuring how a page feels to the person using it. There are three of them, and each one answers a simple question.
The three measurements
Largest Contentful Paint (LCP): how quickly does it appear?
LCP measures how long the main content of the page, often a large image or headline, takes to show up. Google considers 2.5 seconds or less to be good.
Interaction to Next Paint (INP): does it respond when I tap?
INP measures how quickly the page reacts when someone taps, clicks or types. A page can look finished and still feel frozen. 200 milliseconds or less is considered good.
Cumulative Layout Shift (CLS): does it stay still?
CLS measures how much the page jumps around as it loads. You know the feeling: you go to tap a button and an image appears, pushing it out of the way. A score of 0.1 or less is considered good.
Why they matter
These measurements are part of how Google assesses page experience, though great content still matters more for rankings. The stronger reason to care is your customers. People on a phone, on a patchy connection, with something else competing for their attention, will not wait around for a slow page.
Lab scores and real visitors
Tools such as PageSpeed Insights can show two kinds of data, and it helps to know the difference:
- Lab data comes from a simulated test run. It is great for finding problems, and it is what produces the familiar score out of 100.
- Field data comes from real Chrome users visiting your site over the previous 28 days. It shows what people actually experience, and it is what Core Web Vitals assessments are based on.
A new or low-traffic page may not have enough visitors to produce field data, so the lab score is all you will see at first.
The first things to check
If your site feels slow, these usual suspects are worth looking at first:
- Oversized images. Use modern formats such as WebP or AVIF, and do not send a phone an image sized for a cinema screen.
- Too many third-party scripts. Chat widgets, trackers and ad tags all compete for the same phone processor. Remove the ones you no longer use.
- Images and embeds with no reserved space. Giving them set dimensions stops the page from jumping as they load.
- Fonts that load late. Host your fonts yourself where you can, and load only the styles you actually use.
- Slow hosting or no caching. A content delivery network can help by serving files from locations closer to your visitors.
Where to go from here
Run your most important pages through PageSpeed Insights, and test on mobile first, since that is usually the tougher result. Do not chase a perfect score at the expense of everything else. Fix what affects your customers most, and work down from there.
If you would like a second opinion, we can review your site with a free SEO audit.
Need a hand with this? Explore our web design services.
