You can use a website speed test tool such as Google PageSpeed Insights or GTmetrix, or use your web browser’s developer tools. In Google Chrome, for example, you can open the developer tools by pressing F12 or right-clicking on the page and selecting “Inspect,” then go to the “Network” tab and reload the page to see how long it takes to load.
If you are using Google Analytics, you can also access the Site Speed reports under the Behavior tab, which are automatically tracked.
Another Google tool that tracks your Core Web Vitals is Google Search Console, which measures real-world usage data of your website.