Free Website Speed Test

Core Web Vitals are the three user-experience metrics Google uses as part of its page experience ranking signals. Each is judged at the 75th percentile of real visits, so three out of four visitors need a good experience for the page to pass.

• Largest Contentful Paint (LCP) — how long until the biggest image or text block is visible. Good is 2.5 seconds or less. Slow servers, large hero images and render-blocking CSS are the usual culprits.
• Interaction to Next Paint (INP) — how quickly the page responds when someone taps, clicks or types, across the whole visit. Good is 200 ms or less. Heavy JavaScript, chat widgets and third-party tags are the common causes of poor INP.
• Cumulative Layout Shift (CLS) — how much content jumps around while the page loads. Good is 0.1 or less. Give images, ads and embeds fixed dimensions and avoid inserting banners above existing content.

Lighthouse lab tests cannot measure INP because no real person interacts with the page, so the lab report shows Total Blocking Time (TBT) as a stand-in: if TBT is high, INP is usually poor too.

The 0–100 performance score is a weighted blend of five lab metrics: Total Blocking Time and Largest Contentful Paint carry the most weight, followed by Cumulative Layout Shift, First Contentful Paint and Speed Index. Each metric is compared with data from real websites, so a score of 50 roughly means you are around the median of the web, and 90+ puts you among the fastest pages.

The accessibility, best practices and SEO scores work differently: they are the weighted share of pass/fail audits your page passes, such as image alt text, colour contrast, HTTPS, valid meta tags and crawlable links.

• Compress and resize images, serve them as WebP or AVIF, and lazy-load anything below the fold — but never lazy-load the main hero image.
• Use a good host or a CDN so the server answers in well under a second (Time to First Byte). Cheap shared hosting is often the single biggest bottleneck for small business sites.
• Remove plugins, sliders, chat widgets and tracking tags you do not really need. Each third-party script competes for the phone’s processor.
• Turn on caching and text compression (gzip or Brotli), and minify CSS and JavaScript.
• Preload the LCP image and the main web font, and use font-display: swap so text appears straight away.
• Set width and height on images and video so the browser reserves space and the layout does not shift.

Yes, but as a tie-breaker rather than a trump card. Relevance and content quality still come first, yet when several pages answer a search equally well, the faster one with better Core Web Vitals has an edge. The bigger effect is on people: slow pages lose visitors before they ever see your offer, and every extra second on mobile measurably reduces enquiries and sales. For local businesses competing in the map pack and organic results, a fast mobile site is one of the cheapest advantages you can buy.