How SpeedCheckTest works

What we measure

SpeedCheckTest measures three core network performance metrics in sequence:

• Ping (latency) — round-trip time in milliseconds. Under 20 ms is excellent for gaming; under 50 ms suits video calls.
• Download speed — how fast your device receives data (Mbps). Affects streaming, page loads, and file downloads.
• Upload speed — how fast your device sends data (Mbps). Affects video calls, live streaming, and cloud uploads.

Test methodology

1. Server selection — we detect your approximate location and auto-select the lowest-latency server from 6 global locations. You can override this in the dropdown.
2. Ping phase — 8 consecutive HTTP round-trip requests. We report the minimum value (best-case latency).
3. Download phase — 4–8 parallel HTTP streams fetch binary payloads over a 10-second window. Multi-stream is essential: a single TCP connection cannot saturate modern high-bandwidth links due to TCP congestion window limits.
4. Upload phase — generated binary data is sent to the server over parallel POST connections for 6 seconds.

Accuracy and limitations

Results reflect your connection to our nearest server at the moment of testing. Factors that affect results include: Wi-Fi interference, router bottlenecks, ISP congestion at peak hours, server load, and device performance. For best accuracy, use a wired Ethernet connection and close other applications. Run multiple tests at different times to build a reliable picture. See our guide on how to get the most accurate speed test result.

Open source

Client-side speed test logic is inspired by LibreSpeed by Federico Dossena. We support transparency in speed test methodology.

Privacy

Your IP address is used only to route your test to the nearest server and is retained for a maximum of 30 days before being purged. Test results stored in your browser's localStorage never leave your device. See our privacy policy for full details.