Core Web Vitals Explained: Simple Ways to Improve LCP, INP and CLS

You open a website, the text takes ages to appear, an ad pops in just as you start reading and pushes everything down, and a button does nothing when you tap it. Most people leave. Google measures exactly these experiences with three numbers known together as Core Web Vitals.

In his earlier writing, Sultan Muhammad Rashed explained that Google changes its algorithm a little every day and occasionally rolls out big updates, and that user experience had become an important part of ranking. One of the three metrics from that time (FID) has since been replaced. This guide uses Google's official information as of November 2026 to explain what Core Web Vitals are, how to measure them and how to fix them.

What are Core Web Vitals?

Core Web Vitals are three metrics defined by Google that measure three sides of real user experience:

• LCP (Largest Contentful Paint): how fast the largest visible element, usually the main image or headline, appears on screen. This is loading speed.
• INP (Interaction to Next Paint): how quickly the page responds after a click, tap or key press. This is responsiveness.
• CLS (Cumulative Layout Shift): how much text, images or buttons move unexpectedly while the page loads. This is visual stability.

From FID to INP: what changed

Responsiveness used to be measured by FID (First Input Delay), which only looked at the delay of the first interaction. According to web.dev, INP became a Core Web Vital on 12 March 2024, replacing FID. INP considers interactions across the whole visit, so sites with heavy JavaScript find it harder to pass. If an article still talks about FID, it is out of date.

What is a good Core Web Vitals score?

Google measures at the 75th percentile. Put simply, a page passes when at least 75% of its visits are within the "good" range for all three metrics. Mobile and desktop are measured separately.

Do Core Web Vitals affect rankings?

Google's Search Central documentation says it highly recommends good Core Web Vitals for success with Search, and that, along with other aspects of page experience, they align with what its core ranking systems seek to reward. Google does not say how much weight they carry.

So avoid two common misunderstandings:

• "A score of 100 will put me on page one." No. Relevant, helpful content always comes first.
• "Speed doesn't matter." Also wrong. On slow, jumpy sites readers leave quickly, and sales and ad income fall.

When rankings move during a Google core update, many people blame speed alone. In reality, core updates mainly reassess content quality; Core Web Vitals are only a supporting part.

Where and how to check Core Web Vitals

1. Google Search Console: under Experience, the Core Web Vitals report shows which pages are Good, Need improvement or Poor, for mobile and desktop. Similar pages are grouped, which makes template problems easy to spot.
2. PageSpeed Insights: enter a URL to see real-user field data at the top (from the Chrome User Experience Report) and a Lighthouse lab test with suggestions below.
3. Chrome DevTools: developers can use the Performance panel to pin down which script or image causes the delay.

Remember that field data and lab data are not the same. Google's assessment uses real-user data. If a new or low-traffic site has no field data yet, start with the lab report.

How to improve LCP

• Serve the main (hero) image in WebP or AVIF at the right size; phones don't need a 2000-pixel image.
• Don't lazy-load the main image in the first screen; give it loading priority instead.
• Cut server response time with good hosting, server caching and a CDN.
• Reduce render-blocking CSS and font files, and remove plugins you don't need.

How to improve INP

• Remove or defer unnecessary JavaScript, pop-ups, chat widgets and tracking scripts.
• Break long JavaScript tasks into smaller pieces so the browser can respond to clicks in between.
• Show a visible response first (such as a loading indicator) when a button is pressed, and do the heavy work afterwards.
• Avoid very large page structures with thousands of elements.

How to improve CLS

• Give every image and video a width and height (or an aspect ratio) so space is reserved before it loads.
• Reserve fixed space for ads and embeds. On an AdSense-supported site this is essential.
• Don't insert banners or notices at the top after the page has loaded.
• Preload web fonts properly so text doesn't jump when the font arrives.

Common problems and quick fixes

A short checklist for WordPress sites

Many blogs and small business sites in Bangladesh run on WordPress. A few steps almost always help:

• Choose a light, fast theme; avoid themes full of animations and sliders.
• Use one caching plugin, not several; two caching plugins together often cause new problems.
• Resize images before uploading, or use a setup that converts them to WebP automatically.
• Delete plugins you don't use instead of just deactivating them.
• Simplify heavy pages built with page builders.
• After each change, compare before-and-after results in PageSpeed Insights so you know which change actually helped.

How to prioritise the work

Start in Search Console with the page groups marked "Poor". Fix the pages that get the most traffic first. Fixing one template, such as your blog post design, can improve hundreds of pages at once. After fixing, click "Validate fix" in Search Console; real-user data takes about 28 days to refresh, so be patient.

If you want to build a career in SEO or need advice on your own business website, you can learn about Sultan Muhammad Rashed's work at sultanmuhammadrashed.com.

Final word: Core Web Vitals are really a measure of respect for your readers. A page that loads fast, responds the moment it is tapped and stays still while being read keeps readers happy and sends Google the right signals.