Trust & legal
Methodology
How this test works, what it measures, and the practical limits of any browser-based speed test.
How the test runs
Live Internet Speed uses Cloudflare's official @cloudflare/speedtest package. When you press "Start Speed Test," your browser opens a series of requests directly to Cloudflare's network — not to our own servers. We never operate or proxy the measurement traffic ourselves. The test runs in several phases: idle latency, a download ramp using progressively larger payloads, and an upload ramp, with latency also sampled while download and upload are active.
What each measurement means
- Download / upload speed (Mbps): throughput measured across multiple requests of increasing size, using the median of samples that ran long enough to be reliable.
- Idle latency (ping): round-trip time to Cloudflare when the connection isn't otherwise busy, taken at the median of several samples.
- Jitter: how much idle latency varies between individual samples.
- Loaded latency: latency measured while download or upload traffic is active, which reveals how much the connection slows down under load (sometimes called bufferbloat).
How we interpret results
Ratings, use-case assessments, and recommendations are produced by deterministic rules in our own code — not a generative AI model — using threshold ranges we maintain and review. These ranges are practical guidance based on typical activity requirements, not universal physical constants, and we adjust them as real-world usage patterns change.
| Metric | Guidance ranges |
|---|---|
| Download | Below 5 Mbps limited · 5–25 basic · 25–100 good · 100–500 very good · above 500 excellent |
| Upload | Below 2 Mbps limited · 2–10 basic · 10–50 good · above 50 excellent |
| Idle latency | Below 20 ms excellent · 20–50 good · 50–100 acceptable · above 100 poor for real-time use |
| Jitter | Below 5 ms excellent · 5–15 good · 15–30 noticeable · above 30 unstable |
| Loaded latency increase | Below 20 ms excellent · 20–50 good · 50–100 noticeable · above 100 likely bufferbloat |
We deliberately avoid over-crediting raw bandwidth: a very fast connection with high latency or jitter under load will not automatically receive an "excellent" rating, because that combination causes real, noticeable problems in games and calls even though a download number alone looks great.
Why results differ from other speed tests
Every speed test measures performance between your device and that provider's own network of servers. Server location, network routing (peering, transit paths), TCP/QUIC implementation details, browser behavior, and the exact testing methodology (payload sizes, sample counts, percentile used) all affect the number you see. A difference between this test and Speedtest.net, Fast.com, or your ISP's own tool does not mean either result is "wrong" — it reflects a different measurement path.
What we don't measure yet
We don't currently measure packet loss. Reliable packet-loss measurement needs a WebRTC TURN relay with securely issued, per-session credentials; Cloudflare's public TURN configuration for this is deprecated, and we chose not to ship an unreliable measurement. We may add it later if a secure credential flow becomes available — see the "detected issues" section of your result for other signals of connection instability in the meantime.
Accuracy
We periodically compare repeated results here against Cloudflare's own speed.cloudflare.com, since we use the same underlying engine. We don't expect — or claim — identical readings from Speedtest.net, Fast.com, or M-Lab; see the explanation above for why.