Tools to measure website speed

The speed of a website has a major impact on the user experience and on Search Engine Optimization (SEO). There are several tools to measure how fast a website loads.

My top 5

1. WebPageTests. Incredible tool with a free plan that lets me run tests and get all major metrics: First Byte, Start Render, First Contentful Paint (FCP), Speed Index, Largest Contentful Paint (LCP), Cumulative Layout Shift (CLS), Total Blocking Time (TBT).
2. PageSpeed Insights.
3. GTmetrix.
4. Pingdom.
5. Dotcom Tools.
6. Bonus. KeyCDN Tools.

Criteria to compare tools

Here are some possible criteria to choose the right tool for your website:

1. The metrics measured. The test of the Core Web Vitals is a must. There are 3 of them: Largest Contentful Paint (LCP), First Input Delay (FID) and Cumulative Layout Shift (CLS). Any tool that does not provide these metrics should be disqualified right away.
2. The device used for the test. Ideally, you should be able to run tests on mobile and desktop.
3. The location of the test. Ideally, you want to test your website in the countries where your visitors are in.
4. The test history. Ideally, you want the tool to keep track of the previous tests you run. You should be able to compare the evolution of the numbers. Your goal is to take action to improve them over time.