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 October 24 (excluding empty values, which resulted in 49,747). Here are the median (p50) values by device type:

Mobile
153ms
Desktop
96ms
All Devices
140ms

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:

Mobile
102ms
119ms
153ms
208ms
267ms
27ms
172ms
1568ms
48,777
All Devices
88ms
108ms
140ms
195ms
259ms
24ms
159ms
1563ms
49,747
Desktop
65ms
76ms
96ms
126ms
170ms
16ms
109ms
965ms
40,740

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
66ms
2.
Norway
75ms
3.
Sweden
78ms
4.
Denmark
80ms
5.
Belgium
84ms
6.
United Kingdom
87ms
7.
Switzerland
87ms
8.
Germany
88ms
9.
Czechia
88ms
10.
Taiwan
88ms
...
...
...
61.
India
202ms
62.
Egypt
213ms
63.
Kazakhstan
217ms
64.
Venezuela
231ms
65.
South Africa
237ms
66.
Sri Lanka
269ms
67.
Iran
273ms
68.
Kenya
273ms
69.
Pakistan
291ms
70.
Nigeria
353ms

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
Adult Content
100ms
125ms
171ms
239ms
295ms
24ms
189ms
834ms
6,586
Arts & Entertainment
95ms
116ms
156ms
216ms
273ms
39ms
173ms
720ms
10,100
Online Communities
89ms
113ms
150ms
210ms
270ms
39ms
168ms
691ms
2,795
Books & Literature
94ms
114ms
148ms
199ms
249ms
54ms
161ms
534ms
1,449
Internet & Telecom
90ms
113ms
145ms
199ms
253ms
30ms
163ms
1563ms
3,210
Law & Government
86ms
106ms
141ms
193ms
242ms
36ms
154ms
570ms
2,189
All ☼
88ms
108ms
140ms
195ms
259ms
24ms
159ms
1563ms
49,747
Finance
84ms
103ms
138ms
184ms
238ms
39ms
152ms
515ms
2,367
Jobs & Education
75ms
96ms
138ms
192ms
249ms
36ms
152ms
624ms
4,543
Computers & Electronics
84ms
105ms
137ms
183ms
240ms
30ms
152ms
1036ms
3,016
Games
84ms
103ms
137ms
181ms
246ms
37ms
151ms
660ms
2,979
News
91ms
109ms
137ms
183ms
243ms
43ms
153ms
788ms
7,593
Sports
90ms
108ms
132ms
180ms
244ms
50ms
153ms
642ms
2,269
Business & Industrial
84ms
102ms
130ms
173ms
236ms
33ms
147ms
1150ms
2,807
Travel & Transportation
90ms
106ms
126ms
159ms
211ms
52ms
141ms
835ms
1,412
Autos & Vehicles
89ms
103ms
121ms
157ms
206ms
45ms
137ms
596ms
1,245
Beauty & Fitness
84ms
99ms
116ms
146ms
197ms
52ms
130ms
375ms
1,054
Food & Drink
85ms
100ms
116ms
147ms
214ms
54ms
133ms
450ms
1,002
Shopping
83ms
97ms
116ms
148ms
200ms
36ms
131ms
712ms
4,785

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.