Understand your internet speed test
Download and upload measure different things
Download speed describes how quickly data reaches your device. It affects large downloads and the number of streams you can watch at once. Upload describes how quickly you send data and matters for video calls, file sharing, and backups. Both are usually shown in megabits per second (Mbps).
A download application may show megabytes per second (MB/s). There are eight bits in a byte, so a 100 Mbps connection has a theoretical ceiling of about 12.5 MB/s before overhead. Confusing these units can make a healthy connection seem slow.
Latency is response time
Latency, often called ping, is the time for a request to reach a server and return. Lower is usually better for games and calls. A nearby server should normally respond faster than an overseas server. Jitter describes how much this delay varies; a stable connection may feel better than one with a high download speed but frequent delay spikes.
Packet loss means some data did not reach its destination. A browser HTTP test cannot directly prove network packet loss. If a tool does not actually measure a metric, treat it as unavailable rather than interpreting zero as a perfect result.
Run a repeatable test
- Use Ethernet where possible. Otherwise stay close to the router and record that you used WiFi.
- Pause cloud backups, streaming, app updates, and VPNs that are not part of the connection you want to test.
- Run the test two or three times. Allow a short pause between runs.
- Repeat at peak evening hours and during a quieter period.
- Compare the same device and test destination; changing either can change the result.
Interpret the result in context
A test measures the path between your device and its test server at that moment. It cannot guarantee the speed of every website or app. A slow result may reflect WiFi interference, device limitations, congestion, or the test server itself. Large tests can consume significant mobile data, so check your allowance first.