Load Times

The first part of the Load Times page is the Timeline graph, which plots the average length of time it takes for three RUM metrics – average time to load, average time to interactive, and average time to first byte (TTFB) – over calendar time. The time axis units depend on the current time filter setting. For example, with the time set to 1 day, the time axis shows units of hours:

Page load time information comes from the Navigation Timing API in modern browsers. Navigation Timing is a JavaScript API that provides a simple way to get accurate and detailed timing statistics for page navigation and load events.

The metrics used are

MetricDescription
Time to page loadThe time between when the browser sends its request for the web page assets (that is, after the DNS lookups are finished and the TCP connection has been established) until the load event occurs.

loadEventStart - requestStart

Time to interactiveThe time between when the browser sends its request for the web page assets (that is, after the DNS lookups are finished and the TCP connection has been established) until the page becomes responsive to user interactions.

domInteractive - requestStart

Time to first byte (TTFB)The time between when the client makes an HTTP request and when it receives the first byte of the response.

We consider 98th percentile data (for each country) based on page load time.

Note

If you want to see all of the raw Navigation Timing information, you can request log delivery with this information included along with the default set of log fields. For assistance with enabling the log delivery service, please contact Support.

If you hover the mouse pointer over a point on the plot, the average values of these metrics are displayed in a box alongside the mouse pointer, with a granularity that depends on the time filter settings.

You can also drag either the left or right side of the zoom control just beneath the timeline to focus on a narrower range of times.

Below and to the left is the Location display. You can hover the mouse pointer over a country on the map to display numeric data for that particular country:

To the right is the Top Countries donut chart. You can hover the mouse pointer over a country on the chart to display numeric data for that particular country:

Finally, there is a sortable table of Slowest Pages By URI:

Click on the column headers to sort the data in ascending or descending order.

A Download CSV button is available on the right if you want to get a CSV file of this table. Click it and the file will download.