Round-Trip Time

Overview

This is an interactive report to explore network latency on the web. It addresses questions such as: What is the current health of the network? How does it vary by domain ending and website categories? It uses Round-Trip Time (RTT) data from Chrome UX Report (CrUX).

RTT shows the time it takes for a request to go from a client to the server and back (round-trip). In CrUX, it is estimated on the initial page load navigation using navigator.connection.rtt and measured in milliseconds. CrUX provides 75th percentile (p75) aggregated for all domain visits during the past 28 days.

RTT is a diagnostic metric that helps you to understand your audience network connection. Instead of relying on 2G, 3G, or 4G labels (which are also based on RTT), it provides better visibility to your visitors' connection. For example, if your site's average RTT is slow, performance metrics like TTFB or LCP are also likely to be impacted. Consider loading some parts of your site conditionally (learn more). But if RTT is fast and you still have slow metrics, you need to optimize your site. To measure your site's performance, use our free Site Speed Test.

Methodology: we took RTT data for the top 50,000 origins of CrUX's August 2026 list, collected on October 1, 2026 (excluding empty values, which resulted in 49,327). Here are the median (p50) values by device type:

On the average origin of the list, 74% of the traffic comes from phones, and the median on all devices (133 ms) lies closer to Mobile's (147 ms) than to Desktop's (92 ms). The table below provides a detailed breakdown of the RTT distribution with percentiles and statistics: