Is your page loading slowly, elements are unresponsive and buttons don’t react? Users definitely get frustrated about this and frequently end up closing the site to look for a more user-friendly alternative. To prevent this, Google introduced Core Web Vitals — a set of metrics that show how easy and necessary it is to interact with a website.
1. What Are Core Web Vitals?
Core Web Vitals are not just technical metrics to check off. These are three key indicators that together form Google’s (and your users’) perception of how comfortable it is to use your website:
- LCP — How quickly the main content appears;
- FID — How quickly the website responds to actions;
- CLS — How stable the elements on the page are.
Google uses these metrics as part of Page Experience, which directly affects a website’s ranking in search results.
Thus, optimizing Core Web Vitals is not just about SEO. It’s about comfort, trust and real actions on the site. If you care not only about getting traffic but also about users staying, subscribing or purchasing, these metrics are definitely something you shouldn’t ignore.
2. Overview of the Main Core Web Vitals Factors
How Largest Contentful Paint (LCP) Works
This metric measures how quickly the user sees the main content: a large heading, image or banner. If it appears instantly, everything is fine. If it takes longer than 2.5 seconds — you risk losing the visitor.
What Can Slow Down LCP?
- Too large images.
- Slow server response.
- Lack of caching.
- Too much JavaScript, which delays the process.
What Can You Do?
- Compress images and use modern formats (e.g., WebP).
- Enable caching — this speeds up repeated loading.
- Use a CDN — so the data comes from the nearest server.
Remember: improving LCP is not just about speed. It’s about how quickly users can start interacting with your website.
How First Input Delay (FID) Works
This metric tracks how quickly the site responds when the user clicks something for the first time. If you click, and the site freezes or “thinks,” that’s a bad FID.
Why This Matters
The thing is, an immediate response creates the “wow, how fast!” feeling, while delays are frustrating.
Ideal Values:
- Up to 100 ms — great.
- 100 to 300 ms — it’s worth considering.
- Over 300 ms — users may leave.
How Cumulative Layout Shift (CLS) Works
This is about how “calm” the page behaves during loading. If everything suddenly starts shifting, disappearing or moving, this results in high CLS.
Imagine: you want to click “Buy,” but the button suddenly shifts and you end up clicking something else. Not pleasant, right?
How CLS is Calculated:
- How much content moved.
- How large the affected screen part is.
The ideal CLS should be less than 0.1. Everything from 0.1 to 0.25 is tolerable, but requires improvement. The parameter over 0.25 is bad and this even affects search results.
3. Why Core Web Vitals Matter for SEO?
Google wants users to not only find useful content but to also have a smooth experience. That’s why, starting in 2021, Core Web Vitals became part of the ranking formula. If a site is user-friendly, fast and doesn’t “jump around,” it has a better chance of ranking high in search results.
What Does Optimization Give You?
When a website works quickly and without glitches, it:
- Builds trust.
- Increases the likelihood of return visits.
- Helps “engage” users for a longer time.
It also impacts conversions. A user-friendly site leads to more subscriptions, purchases and registrations because when everything is clear and pleasant, users have the desire to stay.
4. How to Check and Analyze Core Web Vitals
Don’t wait for users to complain. Check your website regularly. Here are a few tools that will help you do that:
- Google PageSpeed Insights — analyzes the page and suggests improvements;
- Google Search Console — shows how the site performs in the eyes of real users;
- Lighthouse — a comprehensive performance, accessibility and SEO audit. Perfect for deep analysis.
- Web.dev — the same data, but with more user-friendly and clear suggestions.
5. Practical Recommendations for Improving Core Web Vitals
To make your site work like a Swiss watch, pay attention to:
- Image Compression
WebP is your friend. Quality remains unchanged, but the file size reduces. - Responsive Images
Don’t load large images on small screens. Set up srcset — and the browser will automatically choose what’s needed. - Caching and CDN
Proper cache settings and CDN integration speed up the site even from the farthest corners of the world. - Light Code
Minimize JavaScript and CSS, load scripts asynchronously. Less “drag” results in better experience. - Fixed Media Sizes
Predefined sizes for images and videos result in reduced shifting and better CLS. - No “Surprises”
All banners, pop-ups and other elements should have a predefined place. Don’t let the content “move around.”
This is all about care. It’s about people who come to your site and want to easily and comfortably find what they need.
Summing Up
Core Web Vitals is not about complex terms. It’s about the experience a person has when visiting your site.
How quickly did the content appear? Was it possible to click something immediately? Did everything go smoothly?
These small details shape the overall impression. It affects trust, the desire to buy something and whether the user will return.
What’s important, this is not a one-time task. You need to come back regularly, check and improve the required parameters. Anyway, a good website is a process, not a one-off event.