How to Speed Up Your Website and Improve Core Web Vitals

Page speed has been a Google ranking factor since 2010 for desktop and since 2018 for mobile. In 2021 Google introduced Core Web Vitals — three specific performance metrics that are now part of the search ranking algorithm. A slow website does not just frustrate users — it actively hurts your search rankings. Here is how to test your speed and fix the issues.

What Are Core Web Vitals?

Core Web Vitals are three user experience metrics Google uses to evaluate page performance:

• Largest Contentful Paint (LCP) — how long it takes for the main content of the page to load. Target: under 2.5 seconds
• Interaction to Next Paint (INP) — how quickly the page responds to user interactions like clicks or taps. Target: under 200 milliseconds
• Cumulative Layout Shift (CLS) — how much the page layout shifts unexpectedly while loading (e.g. images pushing text down). Target: under 0.1

Pages that pass all three thresholds are given a "Good" Core Web Vitals status in Google Search Console, which is a positive ranking signal.

How to Test Your Website Speed for Free

Use these free tools on SEO Stack Tools to assess your current performance:

• Page Speed Checker — see your overall load time and performance grade
• PageSpeed Insights Checker — pulls data from Google's own PageSpeed Insights API for your Core Web Vitals scores
• Mobile Friendly Test — check whether Google considers your pages mobile-friendly
• GZIP Compression Checker — verify whether your server is compressing files before sending them

Common Page Speed Issues and How to Fix Them

1. Images Not Optimised

Oversized images are the single most common cause of slow pages. Always compress images before uploading. Use our Image Optimizer, Compress JPEG, or Compress PNG tools to reduce file sizes without visible quality loss. Also resize images to the exact dimensions they will be displayed — uploading a 4000px wide image to display at 800px wastes significant bandwidth.

2. No Browser Caching

Browser caching stores static files on the visitor's device so they do not need to be re-downloaded on each visit. Configure cache headers in your .htaccess file. Use our Htaccess Generator to generate the correct directives.

3. GZIP Compression Disabled

GZIP compresses your HTML, CSS and JavaScript files before sending them to the browser — typically reducing transfer size by 60–80%. Check whether it is enabled using our GZIP Checker. If it is not enabled, add the appropriate directives to your .htaccess or server config.

4. Render-Blocking JavaScript and CSS

Scripts and stylesheets that load in the block the browser from rendering the page. Minify your code using our HTML Minifier, CSS Minifier and JavaScript Minifier, and load non-critical scripts with the defer or async attributes.

5. Slow Server Response Time

If your server is slow, even a perfectly optimised page will feel sluggish. Check your server response time with our Response Time Checker. If your Time to First Byte (TTFB) is over 600ms, consider upgrading your hosting plan or switching to a faster provider.

How Fast Should Your Website Be?

As a target: your pages should fully load in under 3 seconds on mobile. For LCP specifically, aim for under 2.5 seconds. Use the PageSpeed Insights Checker monthly to track your progress and ensure that new content or plugins have not introduced regressions.

Speed optimisation is not a one-time task — it is ongoing maintenance. The faster your site, the better your rankings and the more conversions you will achieve.