Programming guide

Speed up a slow-loading web page

Measure what makes a web page slow, fix the biggest problems such as heavy images and scripts, and check the page is faster for real visitors.

Estimated time: 1–2 hoursUpdated: 28 September 2026

Use this guide when visitors complain your site is slow or a performance report scores poorly. Have access to the site's code or content management system and a browser with developer tools.

Step by step

  1. Measure a baseline

    Run a performance test on your slowest important page using your browser's built-in Lighthouse or performance panel. Note the key measures, such as Largest Contentful Paint and total page weight, and save the report. Test on a simulated mobile connection, as that is how many people visit.

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