How we measure your speed
This page explains how the Pulse speed test works and what its limits are.
What we measure
- Download speed — How fast data can be downloaded to your device, in megabits per second (Mbps). We stream a fixed amount of data from a CDN and time how long it takes.
- Latency — The round-trip time in milliseconds (ms) for a small request to the same CDN. Lower is better for video calls and gaming.
- Jitter — The variation in that round-trip time. Stable connections have low jitter.
We do not measure upload speed in the current version.
How we try to keep results reliable
- We use multiple runs and show the median as the main number, so one-off spikes or dips have less effect.
- Every test request is cache-busted so your browser or a proxy does not serve old data.
- Latency and jitter are measured by sending several small requests to the same CDN we use for the download test (internet path, not just your home network).
- We show a confidence label (High, Medium, or Low) when relevant (e.g. tab in background).
Limits and caveats
- Browser and device — The test runs in your browser. Your device’s CPU and other apps can affect the result. For a fair test, use an Ethernet cable and close other heavy apps.
- Single endpoint — We use one CDN for the test. Your speed to other services may differ.
- No server-side storage — We do not store your results, IP, or precise location. Any location shown is approximate and from a third-party service; we do not keep it.
What “good” speed means in the UK
Regulators (e.g. Ofcom) often suggest at least 10 Mbps for a typical household. For several users or 4K streaming, 30–100 Mbps or more is commonly recommended. Needs vary by household.