Your connection,
timed.

The three numbers in a speed test

Mind the units: internet plans are sold in megabits per second (Mbps), while download managers often show megabytes per second (MB/s). One byte is 8 bits, so a 400 Mbps connection downloads at about 50 MB/s at best.

How Volt measures your connection

Volt relies on M-Lab (Measurement Lab), an open measurement platform founded by researchers and supported by partners including Google. When the test starts, Volt asks M-Lab for the server nearest to you, then uses the ndt7 protocol:

1. Download: for 10 seconds, the server sends you random data as fast as it can, and Volt counts the bytes received.
2. Upload: for 10 seconds, your browser sends random data back. The speed kept is the one counted by the server, not the one estimated by your browser, which could overstate it.
3. Ping: Volt reads the minimum latency measured by the server at the TCP level, which is more reliable than a simple HTTP round trip.

M-Lab servers are connected at 10 Gbps and spread around the world, so the server is not what limits the result, even on very fast fibre. If M-Lab cannot be reached, for example behind a corporate firewall that blocks WebSockets, Volt shows a failure message rather than an approximate figure.

What speeds do you need?

For a household, add up simultaneous uses: two 4K screens, a video call and background downloads already need more than 60 Mbps. For gaming and video calls, ping matters more than speed: 1 Gbps fibre with 80 ms of latency will feel worse for gaming than a 50 Mbps connection with 15 ms.

Getting a reliable result

• Use Ethernet if you can. Wi-Fi adds losses, especially through walls, and often tops out well below fibre speeds.
• Close anything using bandwidth: downloads, cloud sync, streaming on other devices in the home.
• Test at different times: in the evening, roughly 8 to 11 pm, your provider's network is busier.
• Turn off your VPN during the test, unless the VPN is what you want to measure.
• Run the test two or three times and keep the most representative value, not the best one.

Your speed is lower than your plan

The advertised speed is a theoretical maximum, measured as close as possible to your provider's equipment. Several things explain a gap:

• Wi-Fi: on 2.4 GHz, a few dozen Mbps is common; on 5 GHz or Wi-Fi 6 you get much closer to the line speed, especially near the router.
• Your device: an old computer or a network card limited to 100 Mbps caps the result, whatever your fibre.
• Line technology: on ADSL or VDSL, speed drops with the length of the copper line to the exchange.
• Network load at peak times, at home and at your provider.

If your speed stays clearly below your plan, over Ethernet and at different times of day, note the results with their dates and contact your provider: regular measurements are a strong argument.

What about 4G or 5G?

On mobile, speed varies widely with coverage, the frequency band in use and the number of people connected to the same mast. A test indoors can give two to ten times less than outdoors. Remember that the test also uses data: on a fast 5G connection, one test can use several hundred megabytes.

Frequently asked questions

Why is my result slower than my plan?

Wi-Fi, other connected devices, the time of day and your computer's limits all affect the result. For a reliable measurement, use Ethernet, close other apps and repeat the test at different times.

Can the test measure very fast fibre?

Yes. The measurement uses M-Lab servers, connected at 10 Gbps and spread worldwide, and the test picks the one nearest to you. A 2, 5 or 8 Gbps line is measured correctly, as long as your device and cable can keep up.

What happens if M-Lab doesn't respond?

Volt shows a failure message. This is deliberate: a test hosted on a single small server would only measure that server, and it is better to say so than to display a wrong figure. Try again from another network if a firewall blocks WebSockets.

Is my data sent anywhere?

The test only exchanges random bytes, no files or content of yours. M-Lab records the measurement itself (speed, latency, IP address) and publishes it as open research data. Volt itself stores no results.

How much data does a test use?

It depends on your speed: about 20 seconds of transfer at full speed. On a 100 Mbps connection, expect roughly 150 to 250 MB. Keep that in mind on a limited mobile plan.