Core Web Vitals for business owners

What Core Web Vitals are

Core Web Vitals are user experience metrics. They measure loading speed, interaction responsiveness, and visual stability [1]Source 1 .

Your customers feel them as slow pages, laggy buttons, and content that jumps around.

Why you should care

Small delays add friction. Friction increases drop-off. Drop-off costs you leads, sales, and donations.

• If the main content loads late, people leave before they understand your offer.
• If the site feels unresponsive, people stop filling forms and stop trusting checkout.
• If the page shifts, people misclick and lose their place while reading [4]Source 4 .

The three metrics in plain English

LCP. Largest Contentful Paint

LCP measures how long it takes for the main content to appear, such as your hero heading, key image, or primary block of text [2]Source 2 .

If LCP is poor, your page feels slow. People bounce before they see what they came for.

INP. Interaction to Next Paint

INP measures how quickly your site responds after a user interacts, such as clicks, taps, typing, opening menus, and submitting forms [3]Source 3 .

If INP is poor, your website feels unreliable. Users tap twice. Forms feel sticky. Checkout feels risky.

CLS. Cumulative Layout Shift

CLS measures how much the page moves around during load, such as text shifting, buttons moving, or banners pushing content down [4]Source 4 .

If CLS is poor, people misclick, lose their reading position, and lose trust.

Targets worth aiming for

Use these as working targets. They suit most small business and charity websites [1]Source 1 .

• LCP. 2.5 seconds or less [2]Source 2 .
• INP. 200 milliseconds or less [3]Source 3 .
• CLS. 0.1 or less [4]Source 4 .

Where the money leaks

Slow first impression, LCP

• Search and social traffic bounces before seeing your message.
• Paid ads waste budget on users who never reach the offer.
• Your best content underperforms because it loads late.

Lag during action, INP

• Users abandon forms because typing and validation feels slow.
• Menu and filter interactions feel unreliable.
• Checkout feels unsafe, even when it works.

Jumpy layout, CLS

• Users click the wrong thing because buttons move [4]Source 4 .
• Users lose their place when reading longer pages [4]Source 4 .
• Cookie banners and widgets shove content around at the worst moment [4]Source 4 .

How to measure without drowning in data

Use real user data where possible. It reflects what visitors experience on real devices and networks [6]Source 6 .

• Use Search Console to see groups of affected pages and scale.
• Use lab tools such as Lighthouse to diagnose causes and test improvements [5]Source 5 .
• Use WebPageTest when you need deeper diagnostics on pages and journeys [7]Source 7 .

Fix order that tends to work

Fixing everything everywhere is slow. Focus on the pages that matter.

• Start with top entry pages, such as your homepage, top service pages, and campaign pages.
• Next, fix conversion pages, such as forms, donate, checkout, and contact.
• Then set budgets and rules so speed does not drift after future edits [9]Source 9 .

Quick fixes that usually improve LCP

• Optimise the hero image. Use correct dimensions, strong compression, and modern formats [2]Source 2 .
• Avoid loading heavy scripts before the main content appears [8]Source 8 .
• Reduce render blocking CSS and JavaScript [2]Source 2 .
• Improve server response time with caching and a CDN where appropriate.
• Remove or delay third-party tags that do not support your main goal [8]Source 8 .

Quick fixes that usually improve INP

• Reduce JavaScript shipped to the browser. Remove unused code and heavy libraries [3]Source 3 .
• Break up long running tasks. Avoid big chunks of work on the main thread [3]Source 3 .
• Defer non-essential scripts until after key interactions [8]Source 8 .
• Audit third-party widgets, chat, tracking, and testing tools. They often cause the lag [8]Source 8 .

Quick fixes that usually improve CLS

• Set width and height for images and embeds so the browser reserves space [4]Source 4 .
• Reserve space for banners and dynamic blocks. Do not insert content above existing content after load [4]Source 4 .
• Avoid late font swaps that change text size and spacing [4]Source 4 .
• Keep cookie banners and pop-ups from pushing content around [4]Source 4 .

Budgets that keep your site fast

Sites slow down over time when nobody defends them. Budgets keep edits honest [9]Source 9 .

• Page weight budget per page type [9]Source 9 .
• Cap third-party scripts, with a quarterly review [8]Source 8 .
• A checklist for new content, images, video, embeds, and fonts.

Next step

If your site feels slow or unreliable, a short performance audit should identify the main causes and produce a prioritised fix plan. You do not need a rebuild to see meaningful improvement.