The ultimate speed test test 2021

The best free online speed tests

TL;DR

The free online speed tests with the least bias is SpeedOf.Me with a bias of -0.4% (and a standard deviation of 0.1Mbps).

The advice above is based on a comprehensive test as described below.

 

Contents

  1. Introduction
  2. Declaration of Interest
  3. What is the best?
  4. Method of measurement
  5. Speed tests to test
  6. The results
  7. Conclusions
  8. Other findings
 

Introduction

Based on previous speed test tests (2020 and 2020 updated) I know the real internet speed I have and the factors that influence a speed test.

In addition, I know that the bias of a speed test is the most important factor to test. Therefore, this speed test only focuses on the biases of the speed tests.

 

Declaration of Interest

In the past I (Hans van der Graaf) programmed my own speed test Internet Speed at a Glance. This because I was often not interested in the exact internet speed. Usually I want a quick indication if there are any problems with the internet connection.

In this speed test test I will treat Internet Speed at a Glance like all other speed tests being tested.

 

What is the best?

For this speed test test, it is assumed that the best speed test has the lowest bias.

 

Method of measurement

Based on an earlier tests, I know that the real internet speed I have is 84Mbps (the ISP used has increased the download speed from 50 to 75 Mbps in 2021).

Each speed test is tested at least 5 times with a clean browser on a wired Linux desktop.

The bias is calculated using the formula: bias = median - expected value, where the expected value is 84Mbps.

 

Speed tests to test

For this speed test test this list of unique speed tests will be used.

 

The results

The following has been measured (and calculated). Note that all values in Mbps.

  1. Bandwidth Place 70.00, 69.91, 69.91, 70.00, 70.08. Standard deviation: 0.07, median:70.00 bias: -14.00
  2. Broadband Internet Speed test (Gone) No meaningful results
  3. Broadband Speed Checker 74.83, 74.95, 74.85, 74.41, 75.00. Standard deviation: 0.23, median:74.85 bias: -9.15
  4. Cloudflare 75.4, 75.2, 75.5, 75.1, 75.4. Standard deviation: 0.2, median:75.4 bias: -8.6
  5. Comparitech 78.68, 81.30, 81.09, 80.89, 82.54. Standard deviation: 1.40, median:81.09 bias: -2.91
  6. DSLReports 75.2, 75.1, 73.8, 76.6, 76.3. Standard deviation: 1.1, median:75.2 bias: -8.8
  7. Fast 76, 63, 64, 52, 69. Standard deviation: 9, median:64bias: -20
  8. Fireprobe 76.18, 76.43, 76.16, 76.38, 76.25. Standard deviation: 0.12, median:76.25 bias: -7.75
  9. Google Fiber 76.1, 76.4, 76.4, 75.9, 76.4. Standard deviation: 0.2, median:76.4 bias: -7.6
  10. Internet Speed at a Glance 50..100, 50..100, 50..100, 50..100, 50..100. Standard deviation: -, median:- bias: -
  11. LibreSpeed 80.2, 81.0, 80.7, 80.8, 80.8. Standard deviation: 0.3, median:80.8 bias: -3.2
  12. Measurement Lab 75.96, 76.05, 75.87, 76.56, 76.10. Standard deviation: 0.27, median:76.05 bias: -7.95
  13. Meter.net 75.05, 74.86, 74.98, 74.72, 75.24. Standard deviation: 0.20, median:74.98 bias: -9.02
  14. N Perf 77.22, 77.11, 77.37, 77.66, 77.38. Standard deviation: 0.21, median:77.37 bias: -6.63
  15. Ookla Speedtest 74.29, 73.52, 74.23, 74.02, 74.50. Standard deviation: 0.37, median:74.23 bias: -9.77
  16. Open Speed Test 79.26, 79.38, 79.19, 78.11, 79.45. Standard deviation: 0.55, median:79.26 bias: -4.74
  17. RCN Speedtest (now redirected to Astound) 77, 77, 65, 77, 77. Standard deviation: 5, median:77 bias: -7
  18. SamKnows 76.4, 76.4, 76.4, 76.4, 76.4. Standard deviation: 0.0, median:76.4 bias: -7.6
  19. SpeedOf.me 83.44, 83.52, 83.50, 83.42, 83.52. Standard deviation: 0.05, median:83.50 bias: -0.50
  20. SpeedSmart 81.61, 79.23, 76.25, 78.31, 78.56. Standard deviation: 1.93, median:78.56 bias: -5.44
  21. Speedtest4.PHP No meaningful results
  22. TestMy.net 77.3, 76.9, 77.1, 76.8, 76.7. Standard deviation: 0.2, median:76.9 bias: -7.1
  23. Toast 53.2, 71.2, 71.8, 71.5, 70.7. Standard deviation: 8.1, median:71.2 bias: -12.8
  24. Xfinity xFi Speed Test 82.7, 79.2, 77.9, 77.2, 79.5. Standard deviation: 2.1, median:79.2 bias: -4.8

Previously I concluded that the max value of SpeedOf.me was most accurate. Hence I also measured these values:

  1. SpeedOf.me max 83.48, 83.52, 83.55, 83.52, 83.53. Standard deviation: 0.03, median:83.52 bias: -0.48
 

Conclusions

Based on the above research, these are the speed tests with the least bias:

The most accurate speed tests
  1. SpeedOfMe with a bias of -0.5Mbps
  2. Comparitech with a bias of -2.91Mbps
  3. LibreSpeed with a bias of -3.2Mbps

Note that taking in account the results of the 2020 speed test tests gives the following results:

Average bias and standard deviation
  1. SpeedOfMe with a bias of -0.4% (standard deviation 0.1Mbps)
  2. Comparitech with a bias of -2.4% (standard deviation 0.9Mbps)
  3. LibreSpeed with a bias of -3.4% (standard deviation 0.2Mbps)

The most consistent speed tests are:

The most consistent speed tests
  1. SamKnows, standard deviation: 0.0
  2. SpeedOf.me, standard deviation: 0.05
  3. Bandwidth Place, standard deviation: 0.07
 

Other findings

Based on the above test and a comparison with the results of previous speed tests, the following can be concluded:

  1. Every speed test has a negative bias.
  2. Since almost every ISP vendor uses or recommends an Ookla-based speed test and the fact that the Ookla Speedtest has a negative bias of -10.5%, I can only conclude that the ISPs have agreed to provide a 12% higher bandwidth than what is advertised.
  3. When the Chromium browser is throtteld at 30Mbps, the real download speed is 34.0Mbps
  4. When the Firefox browser is throtteld at 30Mbps (Wi-Fi), the real download speed is 34.4Mbps