Page speed

The script times every page load in your visitors’ own browsers, and the Speed page shows how fast the site is for them.

Unlike a test from your own computer, these timings come from your visitors’ own phones and connections, rated by Google’s thresholds, including the Core Web Vitals its search takes into account. The pages with the most poor loads are listed, so you know where to start. The tag you already have measures it all.

The six measures

• TTFB, time to first byte: how long the server took to start answering.
• FCP, first contentful paint: when the first text or image appeared.
• LCP, largest contentful paint: when the largest text or image appeared, usually when the page looks loaded.
• INP, interaction to next paint: how long the page took to respond to a click, tap or key press, at its slowest. Only a page the visitor used has one.
• CLS, cumulative layout shift: how much the page jumped about as it loaded, as a score rather than a time.
• PLT, page load time: when the browser finished loading the page and everything on it.

LCP, INP and CLS are Google’s Core Web Vitals.

Ratings

Each is rated good, needs improvement or poor, by Google’s thresholds. PLT has no standard, so fivebar sets its own.

Anything in between needs improvement. A measure a browser can’t take is left out for that page load rather than counted as nought, so each tile says how many page loads it’s from.

The Speed page

Open it from the Overview, Speed, Errors and Bots switch under the site’s name. The dot beside Speed gives the Core Web Vitals at a glance: green when LCP, INP and CLS are all good, otherwise amber or red for the worst of them. Hover over it for each one’s figure. A measure with no page loads, such as INP where nobody clicked, is left out.

The page keeps the dashboard’s dates and filters. At the top is a tile for each measure, with:

• its 75th percentile: three in four page loads were at least this fast
• how far it moved since the period before, in the same unit, with the earlier figure in its tooltip
• its rating, and the share of page loads that were good, needed improvement and were poor
• the same figure for phones, tablets and desktops
• how many page loads it was measured on

The 75th percentile is what Google rates a site by. It reflects most visitors without letting the fastest hide the slowest, as an average would.

Below the tiles is one measure in detail, LCP unless you pick another:

• a chart of its 75th percentile for each day, week or month of the range, with dashed lines where good ends and poor begins
• its 75th percentile by device, browser and country, each with how many page loads it’s from; click any of them to filter the page
• the pages with the most poor loads, each with its 75th percentile, its page loads and the share that were poor. For LCP and INP, the full list of pages with a poor load is a click away.

What is measured

• Each page load once, reported when the visitor leaves it or switches away, since LCP, INP and CLS aren’t final until then.
• Not the pages a single-page app moves to, which load nothing.
• Not paints made while the page was in a background tab, so a page opened in the background has no FCP or LCP, and one closed before it was ever shown has no CLS either.
• A prerendered page is timed from when the visitor went to it.
• Not error pages.

Under a filter, the Speed page times the page loads that match: filtered by a page, that page’s own. It has nothing to show when the range has no measured page loads, or when filtered by an entry or exit page, or by a goal.