We record the following metrics for every pageview (all in milliseconds):
- TTFB: Time to First Byte. How long until the browser receives the first byte from the server.
- FCP: First Contentful Paint. How long until the first text or image appears on screen.
- LCP: Largest Contentful Paint. How long until the biggest visible element (image/text) is loaded
- CLS: Cumulative Layout Shift. How much elements unexpectedly jump around while loading.
- INP: Interaction to Next Paint. How fast the page visually responds after a user interaction.
- page_load_time: Total time for the page to entirely load
In your Dashboard, you will see the average for each measure plus a rating (Good / bad / needs improvement). This is calculated based on all the pageviews within the date range you have selected, so if you have recently implemented some speed improvements, adjust the date range to only include the dates post-implementation, or compare to the previous period.
If you want to perform more complex analysis of your pagespeed performance, this data is fully explorable and exportable using the Data Explorer. This allows you do things like:
- Review total page load time by page or website section, to identify slow pages or technical problems.
- Combine performance data with SEO data, to quantify the organic search impact of pagespeed optimisations.
- Diagnose performance issues by synchronising granular pagespeed data with deployments.