UK West · Cardiff, GB. How long a round trip from your machine to this region takes — and how much of that distance alone demands.
| Cloud | Microsoft Azure |
|---|---|
| Region code | ukwest |
| Region name | UK West |
| Datacentre city | Cardiff, GB |
| Coordinates | 51.48, -3.18 |
| Published IPv4 prefixes | 541 |
| Probe endpoint | https://ukwest.livediagnostics.monitor.azure.com/ |
| Probe style | timed blind — the endpoint sends no CORS headers |
| Verification | Resolved to an address inside this region’s own published range, TCP 443 open. Checked 2026-08-21. |
Coordinates are the real datacentre city rather than the marketing region name, because they feed the distance maths below.
Light in fibre covers about 100 km per millisecond of round trip. These are the great-circle distances to Cardiff and the latency no network can beat — not a measurement, a limit. What you actually measure is this plus routing.
| From | Distance | Floor |
|---|---|---|
| New York | 5,370 km | 54 ms |
| Los Angeles | 8,598 km | 86 ms |
| São Paulo | 9,358 km | 94 ms |
| London | 211 km | 2.1 ms |
| Frankfurt | 846 km | 8.5 ms |
| Johannesburg | 9,162 km | 92 ms |
| Dubai | 5,682 km | 57 ms |
| Mumbai | 7,403 km | 74 ms |
| Singapore | 11,054 km | 111 ms |
| Tokyo | 9,668 km | 97 ms |
| Sydney | 17,176 km | 172 ms |
Within 75 km of Cardiff — near enough that distance sets no meaningful floor between them. When several sit in one city, the fastest is the city’s real floor; a slower neighbour is usually the endpoint’s own server time.
These figures are geometry. Your own round trip to ukwest depends on your connection and the route it takes — open the instrument, pick Azure, and sweep. Every region is timed from your browser against the endpoint listed above, and the result is split into the part physics demands and the part the network added.
See every Azure region on the Azure latency page.