Round-Trip Time

Deep dive into network latency on the web: an interactive report based on Round-Trip Time (RTT) data from Chrome UX Report (CrUX).

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 country 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. We tried to define fast & slow buckets on the map below. To measure your site's performance, use our free Site Speed Test.

Methodology: we took RTT data for the top 50,000 domains aggregated during December 24 (excluding empty values, which resulted in 49,543). Here are the median (p50) values by device type:

Mobile
151ms
Desktop
96ms
All Devices
139ms

Usually, 70% of a website's traffic is mobile, which explains why the All Devices value is closer to Mobile than Desktop. The table below provides a detailed breakdown of the RTT distribution with percentiles and statistics:

Desktop
64ms
75ms
96ms
126ms
173ms
19ms
109ms
905ms
40,065
All Devices
84ms
102ms
139ms
196ms
265ms
29ms
159ms
1660ms
49,543
Mobile
94ms
114ms
151ms
209ms
271ms
31ms
170ms
1665ms
48,695

Geography

Let's explore RTT by country. The regional difference is clear and reflects countries' GDP and the location of data centers. Australia and New Zealand famously experience higher RTT due to speed of light limitations, as data centers are primarily located in the US and Europe. We computed regional RTT using top-level domains (TLDs). For example, .nl represents the Netherlands, and .ca is Canada.

The map below displays the median RTT (p50). And the table on the right lists the top 10 fastest and slowest countries. You can interact with the map and use the device switch to change aggregation.

:
All Devices
MobileDesktop
<100ms
100–150ms
150–200ms
200–250ms
>250ms
Rank
Country
p50
1.
Netherlands
59ms
2.
Norway
70ms
3.
Sweden
73ms
4.
Denmark
74ms
5.
Switzerland
77ms
6.
Belgium
78ms
7.
Germany
80ms
8.
United Kingdom
80ms
9.
Czechia
81ms
10.
Taiwan
81ms
...
...
...
61.
Saudi Arabia
205ms
62.
Egypt
212ms
63.
Uzbekistan
217ms
64.
Venezuela
234ms
65.
South Africa
243ms
66.
Kenya
259ms
67.
Sri Lanka
270ms
68.
Iran
281ms
69.
Pakistan
294ms
70.
Nigeria
366ms

Categories

The network latency varies up to 50% by website category. Sectors like E-commerce or Auto-industry tend to invest more in web performance, resulting in lower RTT. In contrast, categories like Entertainment or Adult content, are much slower. To classify websites, we used Chrome's topic classifier (chrome://topics-internals/). Below is an interactive table to explore the network latency across different clusters of the web:

:
All Devices
MobileDesktop
Food & Drink
79ms
93ms
110ms
145ms
216ms
48ms
129ms
447ms
1,142
Shopping
79ms
93ms
110ms
144ms
196ms
37ms
127ms
682ms
4,924
Beauty & Fitness
79ms
93ms
111ms
143ms
196ms
49ms
127ms
447ms
1,100
Autos & Vehicles
84ms
99ms
117ms
159ms
206ms
42ms
135ms
550ms
1,185
Travel & Transportation
83ms
100ms
121ms
161ms
214ms
49ms
140ms
925ms
1,395
Business & Industrial
81ms
96ms
127ms
177ms
241ms
30ms
147ms
1021ms
2,841
Sports
84ms
100ms
128ms
178ms
249ms
53ms
150ms
1660ms
2,142
News
83ms
100ms
132ms
181ms
250ms
39ms
151ms
853ms
7,507
Games
81ms
99ms
134ms
183.5ms
252ms
36ms
152ms
644ms
3,132
Computers & Electronics
80ms
100ms
135ms
189ms
246ms
40ms
153ms
1065ms
3,021
Finance
81ms
98ms
137ms
188ms
252ms
40ms
154ms
690ms
2,469
All ☼
84ms
102ms
139ms
196ms
265ms
29ms
159ms
1660ms
49,543
Law & Government
84ms
102ms
140ms
192ms
240ms
35ms
154ms
612ms
2,073
Jobs & Education
77ms
99ms
144ms
201ms
256ms
33ms
158ms
765ms
3,714
Books & Literature
89ms
106ms
145ms
197ms
246ms
48ms
158ms
521ms
1,407
Online Communities
84ms
105ms
146ms
208ms
270ms
39ms
165ms
715ms
2,842
Internet & Telecom
86ms
108ms
147ms
204ms
264ms
33ms
166ms
1643ms
3,264
Arts & Entertainment
90ms
111ms
155ms
219ms
280ms
39ms
173ms
1107ms
10,472
Adult Content
94ms
120ms
168ms
240ms
304ms
29ms
189ms
1248ms
6,541

Next: This is the first iteration of the report. We plan to expand its functionality once more RTT data is available in CrUX. Feel free to contact us via Email or Twitter and suggest your ideas and improvements.