How does this speed test work?
This test uses NDT (Network Diagnostic Tool), the open measurement method run by Measurement Lab (M-Lab), a research consortium backed by universities and Google. When you press Start, your browser connects to the nearest M-Lab server and transfers data as fast as the connection allows for about ten seconds in each direction: first download, then upload. The speed is the amount of data moved divided by the time it took.
NDT measures a single connection, the way one download, one video stream or one upload actually moves through your network. Some other tests open several connections at once and add them up, which usually gives a higher number on fast or long-distance links. Neither is wrong: a multi-connection test shows your line's capacity, and NDT shows what a single transfer really gets. If the two differ a lot, the gap is often latency or packet loss on the route.
What's the difference between Mbps and MB/s?
Internet speeds are quoted in megabits per second (Mbps), but file sizes are in megabytes (MB). There are 8 bits in a byte, so divide the speed by 8 to get megabytes per second. At 100 Mbps you download about 12.5 MB every second: a 50 MB video takes 4 seconds, and a 4 GB game update about 5½ minutes, if nothing else slows it down.
Latency, shown in milliseconds (ms), is the time a small piece of data takes to reach the server and come back. It's what makes a connection feel responsive. Under 20 ms is excellent, 20 to 50 ms is good, and above 100 ms you'll notice lag in games and a delay in video calls, however high the download speed is.
How much internet speed do I need?
Rough guides from the major streaming and video-call services:
- HD video streaming: about 5 Mbps per stream. 4K streaming: about 15 to 25 Mbps per stream.
- HD video calls on Zoom, Meet or Teams: about 3 to 4 Mbps in both directions per person on the call.
- Online gaming: 10 to 25 Mbps is plenty; low latency matters far more than raw speed.
- Uploading videos, cloud backup and live streaming: upload speed is the limit, and 10 Mbps or more makes a real difference.
- A household of three or four people streaming, calling and gaming at once: 100 Mbps or more.
How do I get an accurate speed test result?
For a test of the line itself, use a computer connected to the router with a cable, close other apps and pause downloads and cloud backups. On Wi-Fi, the result is your Wi-Fi speed, which is often the real bottleneck. Run the test two or three times, and at different times of day: evening slow-downs show up clearly when you compare 9 a.m. with 9 p.m.
Turn off your VPN for the test, unless you're trying to measure the VPN. VPNs route your traffic through a distant server and often halve the result.
What can I do if my internet is slower than it should be?
Work through these in order:
- Restart the router and modem: unplug them for 30 seconds. It clears a surprising number of problems.
- Move closer to the router, or connect to its 5 GHz network (often named with “5G”). It's much faster than 2.4 GHz at short range.
- Check other devices: a console update, a TV streaming in 4K or a phone backing up photos can take most of the bandwidth.
- Test with a cable. If the cable is fast and Wi-Fi is slow, the fix is better Wi-Fi (a mesh system or a better router position), not a faster plan.
- If a cabled test is well below what you pay for, at different times of day, contact your provider with the results.
Who sees my speed test results?
M-Lab publishes every test result as open data that researchers, regulators and journalists use to study internet quality. Results include your IP address and the time of the test, but not your name or anything from your device. That's why the page asks you to agree before the test starts. download.fan doesn't store your results.