## TL;DR

With an advertised download speed of 200 Mbps, a speed test uses an average of 0.4 Gigabytes of data. This is also the median. The most popular speed test (the Ookla Speedtest) uses 0.5 Gb.

If you do not want to use too much data for a speed test and still want to know your internet speed accurately - at an advertised speed of 200Mbps - it is best to use TestMy.net or Google Fiber.

## Contents

## Introduction

Our internet provider recently doubled the internet speed from 100 Mbps to 200 Mbps.

For this test we want to know how much data a speed test uses when the advertised download speed is 200 Mbps.

## Method of measurement

The amount of data used by a speed test is measured with the live option of vnstat.

Initially the webpage with the speed tests to test is opened in the Edge browser. Then the data monitoring is started with vnstat -l and the to be tested speed test is opened in a new tab. After three times testing the internet speed, vnstat is stopped with control-C.

The measured download speeds and the median are noted. These are all in mega bits per seconds. The data used as measured by vnstat is in mebibytes (MiB) (or kibibytes (KiB)).

## Speed tests to test

Because this is a relative simple test, the unique speed tests as collected at ZOMDir will be tested.

## The measurements

The following has been measured. Note that all speeds are measured in Mbps.

- Astound Measurements: 209.00, 205.00, 206.00. Median: 206.00 - Sum down 1.65 GiB, sum up 33.40 MiB
- Bandwidth Place Measurements: 183.4, 188.7, 189.1. Median: 188.7 - Sum down 270.82 MiB, sum up 157.32 MiB
- Bredbandskollen Measurements: 203.86, 204.50, 204.78. Median: 204.50 - Sum down 730.42 MiB, sum up 129.8 MiB
- Broadband Speed Checker Measurements: 199.95, 196.00, 205.69. Median: 199.95 - Sum down 916.69 MiB, sum up 157.85 MiB
- Cloudflare Measurements: 202, 202, 202. Median: 202 - Sum down 1.38 GiB, sum up 169.10 MiB
- Comparitech Measurements: 216.75, 216.26, 216.84. Median: 216.75 - Sum down 1.25 GiB, sum up 232.44 MiB
- DSLReports Measurements: 202.3, 201.5, 206.8. Median: 202.3 - Sum down 961.92 MiB, sum up 270.83 MiB
- Fast Measurements: 200, 210, 220. Median: 210 - Sum down 1.04 GiB, sum up 35.60 MiB
- Fireprobe Measurements: 203.93, 203.26, 204.17. Median: 203.93 - Sum down 1.18 GiB, sum up 185.88 MiB
- Google Fiber Measurements: 203, 204, 203. Median: 203 - Sum down 415.00 MiB, sum up 96.25 MiB
- Internet Speed at a Glance Measurements: 50..100, 50..100, 50..100. Median: 50..100 - Sum down 95.86 KiB, sum up 21.7 KiB
- LibreSpeed Measurements: 212, 219, 212. Median: 212 - Sum down 383.79 MiB, sum up 124.11 MiB
- Measurement Lab Measurements: 199.45, 201.86, 201.88. Median: 201.86 - Sum down 739.61 MiB, sum up 128.90 MiB
- Meter.net Measurements: 208.8, 199.9, 202.1. Median: 202.1 - Sum down 372.15 MiB, sum up 92.75 MiB
- N Perf Measurements: 204.8, 205.3, 205.2. Median: 205.2 - Sum down 1.69 GiB, sum up 224.55 MiB
- Ookla Speedtest Measurements: 202.85, 203.71, 204.31. Median: 203.71 - Sum down 1.22 GiB, sum up 202.26 MiB
- Open Speed Test Measurements: 208.65, 208.84, 207.27. Median: 208.65 - Sum down 1.11 GiB, sum up 164.90 MiB
- SamKnows Measurements: 196, 203, 204. Median: 203 - Sum down 957.90 MiB, sum up 208.46 MiB
- SpeedCheck Measurements: 196.51, 207.04, 208.44. Median: 207.04 - Sum down 1.50 GiB, sum up 147.75 MiB
- SpeedOf.me Measurements: 192.68, 199.18, 193.15. Median: 193.15 - Sum down 816.52 MiB, sum up 189.75 MiB
- SpeedOf.me API Sample Page Measurements: 201.66, 204.27, 203.68. Median: 203.68 - Sum down 809.99 MiB, sum up 87.93 MiB
- SpeedSmart Measurements: 206.9, 208.1, 207.6. Median: 207.6 - Sum down 912.65 MiB, sum up 147.97 MiB
- Speedtest4.PHP Measurements: -, -, -. Median: - - Sum down 10.44 MiB, sum up 424.94 KiB
- TestMy.net Measurements: 203.8, 201.8, 201.9. Median: 201.9 - Sum down 272.02 MiB, sum up 6.34 MiB
- Toast Measurements: 40.1, 37.1, 42.5. Median: 40.1 - Sum down 69.21 MiB, sum up 1.52 MiB
- Which Broadband Checker Measurements: 243, 225, 223. Median: 225 - Sum down 804.31 MiB, sum up 138.29 MiB
- Xfinity xFi Speed Test Measurements: 205.3, 205.9, 205.1. Median: 205.3 - Sum down 1.09 GiB, sum up 23.45 MiB

## Conclusions

The least data is used by Internet Speed at a Glance. This speed test uses 39 kibibyte per test. However, this speed test only gives an indication of your internet speed.

N Perf needs the most data for a speed test. N Perf uses 652 mebibytes per test.

The median and average are relative close to each other at 358 and 350 mebibytes respectively.

If we only look at speed tests whose measured values meet the -Accurate and consistent- requirements in What makes a speed test excellent?, the following speed tests meet these requirements:

- Astound
- Bredbandskollen
- Cloudflare
- DSLReports
- Fireprobe
- Google Fiber
- Measurement Lab
- Meter.net
- N Perf
- Ookla Speedtest
- SamKnows
- SpeedOf.me API Sample Page
- TestMy.net
- Xfinity xFi Speed Test

Ideally, you would expect a relationship between the amount of data used and the accuracy of a speed test.

The graph below plots accuracy against the amount of data used. At a glance it is clear that our expectations were not met.

The graph above makes it clear that if you do not want to use too much data for a speed test and still want to know your internet speed accurately - at an advertised speed of 200Mbps - it is best to use TestMy.net or Google Fiber.