How to Run an Accurate Speed Test: Steps and How Many Times

Published: 2026-11-12 ／ Author: Yuki Nakazawa

A speed test gives a slightly different number every time you run it, even on the same connection. If you decide your internet is "slow" based on a single result, you can easily end up blaming the wrong thing.

In this article you will learn: the steps for measuring accurately (as a checklist), why results vary, what to watch out for when testing on a phone, how many times to test, and how this site's speed test actually takes its measurements.

A checklist for accurate results

Before you start, line up the conditions below. The more you want to know what the connection itself can do, the more closely you should follow them, starting from the top.

What to doWhy
Test on a computer connected by an Ethernet cableWi-Fi speed can drop because of signal strength or the wireless capability of the device. A wired connection tends to get you closer to what the line itself can deliver
Stop traffic on other devicesVideo streaming or game downloads on other devices share the same connection, so your result can come out lower by that amount
Turn off your VPNA VPN can send your traffic on a longer route to the test server, which can lower the speed and raise the ping
Close other browser tabs and appsOperating system and app updates, cloud sync and similar tasks may be using the connection in the background
Run 3 tests in a row at the same time of dayThis smooths out the swing from one run to the next. Record the median, explained below
Compare morning, afternoon and eveningMore people are online from late afternoon into the evening, and congestion can pull speeds down
Check which server you are testing againstIf the test server is far away, speed tends to drop and ping tends to rise, even on the same connection

The help pages of Ookla (the company behind Speedtest.net) also suggest that if your connection feels slow, you should close any downloads or video calls in progress and test again, and try restarting your device and router.

Why speed test results vary

A speed test measures the speed between the device in front of you and a test server. If anything along that path changes, the result changes too. Google's help page explains that results can differ because of changing network conditions, the location of the test server and differences in testing methods, and that they can change even over a short period of time.

  • The test server: In general, a closer server gives a faster result. If the test server changes, the numbers change with it.
  • The route: The path your data takes across the internet (its routing) is decided by your internet provider. If the route to the test server is busy, the result will be slower.
  • Time of day: Your provider's equipment may be shared with neighbors or other people in the same building. Speeds tend to drop at busy times.
  • Device performance: Every device has different Wi-Fi and mobile capabilities. An older device may not be able to use the full speed of your connection.
  • The browser: Browsers handle the work of a speed test in different ways, and Ookla's help pages note that this can make a difference, especially on fast connections.
  • Wi-Fi: Distance from the router, walls, and interference from things like microwave ovens can make a big difference. Sometimes the router itself cannot handle the speed you are paying for.

For a look at how different tools measure, see our comparison of speed test tools.

How many times to test (take the median of 3)

As a rule of thumb, run 3 tests in a row under the same conditions. Put the three results in order from smallest to largest and record the middle one. This middle value is called the median.

The reason to use the median rather than the average is that a single extreme result will not drag it around. For example, if your download results were 280, 95 and 300 Mbps, the average is about 225 Mbps, but the median is 280 Mbps. The 95 Mbps result may have been caused by something temporary, such as an update running in the background.

If all three results are very different from each other, your conditions may not be consistent. Go back over the checklist and test again. If you want to see how the time of day affects your connection, run 3 tests each in the morning, afternoon and evening, and compare the medians. Writing down the date, time and numbers also gives you something concrete to show your internet provider if you need to contact them.

Tips for testing on a phone

  • Check which connection you are testing: While your phone is connected to Wi-Fi, you cannot measure your mobile data connection, and the reverse is also true. To test mobile data, turn Wi-Fi off.
  • Test in the same place: Wi-Fi speed can change a lot with distance from the router, and mobile data can change a lot depending on whether you are indoors or outdoors, or next to a window. When comparing results, stay in one spot.
  • Watch your data usage: The faster the connection, the more data a single test uses. This site keeps sending and receiving data for 12 seconds each for download and upload, so at 100 Mbps down the download part alone uses about 150 MB (100 Mbps × 12 seconds ÷ 8). If your plan has a data cap, avoid running test after test.
  • Keep the device's limits in mind: Older phones support older Wi-Fi standards, so the result may hit a ceiling even when the connection itself is fast.

If your phone is slow but a wired computer is fast, the cause may lie with Wi-Fi or the device rather than the connection. For help narrowing down the cause, see our guide to the causes of slow internet.

How this site measures

This site's speed test runs on LibreSpeed, which is open source (LGPLv3). It uses no ads and no third-party trackers. The test settings are as follows.

ItemThis site's setting
Order of the testGet IP address → download → upload → ping and jitter (with a 1-second pause between download and upload, and between upload and ping)
Download test duration12 seconds
Upload test duration12 seconds
Automatic shortening of the testNone (the test runs for the full 12 seconds even on a fast connection)
Grace time (time discarded before measuring starts)0 seconds for both download and upload
Transfer methodSeveral HTTP connections are used at the same time to keep sending and receiving dummy data
Test serverThe location with the lowest ping is selected automatically from our own server in Sapporo plus 37 public mirrors around the world (from Japan's main island of Honshu, this is usually "Tokyo")

Grace time is a waiting period that leaves the start-up phase, before a transfer gets up to speed, out of the measurement. This site sets it to 0 seconds, so the result covers the full 12 seconds, including the start-up phase.

Ping and jitter are measured after download and upload have finished, while the connection is idle. Ping is the response time, and jitter is how much that response time varies. You can also change the test server by hand on the screen, but if you choose a location in another country, ping will rise with the distance and you are less likely to reach your full speed. When you want to see what your connection can do, leave the server on automatic selection. For more on how to read ping, see our guide to ping.

Compare your results with the guidelines

Once you have your median, compare it with the guidelines this site uses throughout. For download speed, under 10 Mbps is not enough, 10–30 Mbps is standard, 30–100 Mbps is plenty, and 100 Mbps or more is fast. The full guidelines, including upload, ping and jitter, and a table by activity are in our internet speed guidelines.

If even a wired connection does not reach the guidelines, suspect the connection or the router. If the wired result is fine but speed drops on Wi-Fi, suspect the Wi-Fi.

FAQ

How many times should I run a speed test for an accurate result?

We recommend running 3 tests in a row under the same conditions and taking the median. The median is less affected by a single extreme result. If you want to see how the time of day matters, run 3 tests each in the morning, afternoon and evening.

Why do I get different results every time I run a speed test?

Because how busy the network is changes from moment to moment. If your connection shares equipment with other users, their usage affects you too. Updates running in the background and the state of your Wi-Fi signal also play a part. It is normal to see some difference even a few minutes apart.

Should I test over Wi-Fi or a wired connection?

If you want to know the speed of the connection itself, use a wired connection. If you want to know what everyday use feels like, test over Wi-Fi in the room you usually use. Testing both lets you tell whether the slowness comes from the connection or from Wi-Fi.

Can I run a speed test with my VPN turned on?

If you want to know the speed of your connection, turn the VPN off. A VPN can send your traffic on a longer route, which can lower the speed and raise the ping. Leave it on only when you want to know your speed through the VPN.

How much data does a speed test use?

It depends on the tool and how fast your connection is. This site measures download and upload for 12 seconds each, so at 100 Mbps down the download part alone uses about 150 MB. Google's help page says the speed test in its search results uses about 4.4 MB per test outside the US.

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