Accuracy check (2) (50 Mbps)

TL;DR

Based on earlier tests the assumption is that the ISP in use delivers a download speed of 56 Mbps, while 50 Mbps must be delivered contractually.

The graph below, based on our tests, clearly shows that there are clusters or categories of speed tests.

Speed test results for a 50Mbps connection in a min avg max diagram

 

Contents

  1. Introduction
  2. Method of measurement
  3. Speed tests to test
  4. The measurements
  5. Conclusions
 

Introduction

When we conducted our tests in 2020, we had only one reference speed: the 50 Mbps advertised by the internet provider. Later tests confirmed our assumption that the true internet speed is 12% higher than advertised.

Based on these later experiences, we've updated this article in 2025. We now indicate whether a speed test is mainstream or realistic. We also provide the accuracy score (based on the median).

 

Method of measurement

All tests have been done with Google Chrome on a wired Windows computer.

 

Speed tests to test

We tested all unique speed tests we were aware of.

 

The measurements

All speed measurements are in Mbps.

  1. Bandwidth Place 46.96, 46.24 and 46.19; Average: 46.5; Median: 46.24; Standard deviation: 0.43; Accuracy score: 20
  2. Broadband Speed Checker 48.30, 50.78 and 51.71; Average: 50.4; Median: 50.78; Standard deviation: 0.99; Accuracy score: 99 Mainstream
  3. Cloudflare 45.9, 48.0 and 47.7; Average: 47.2; Median: 47.7; Standard deviation: 1.14; Accuracy score: 20
  4. Comparitech 55.31, 55.25 and 54.61; Average: 55.1; Median: 55.25; Standard deviation: 0.39; Accuracy score: 96 Realistic
  5. DSLReports 51.8, 50.3 and 50.7; Average: 50.9; Median: 50.7; Standard deviation: 0.78; Accuracy score: 99 Mainstream
  6. Fast 46, 42 and 45; Average: 44; Median: 45; Standard deviation: 2.1; Accuracy score: 20
  7. Fireprobe 51.40, 51.24 and 50.21; Average: 51.0; Median: 51.24; Standard deviation: 0.65; Accuracy score: 95 Mainstream
  8. Google Fiber 51.1, 51.3 and 51.7; Average: 51.4; Median: 51.3; Standard deviation: 0.31; Accuracy score: 94 Mainstream
  9. Internet Speed at a Glance 50..100, 50..100 and 50..100; Accuracy score: 20
  10. LibreSpeed 54.1, 54.3 and 54.4; Average: 54.3; Median: 54.3; Standard deviation: 0.15; Accuracy score: 70
  11. M-Lab 50.82, 51.13 and 51.17; Average: 51.0; Median: 51.13; Standard deviation: 0.19; Accuracy score: 96 Mainstream
  12. nPerf 51.49, 51.59 and 51.45; Average: 51.5; Median: 51.49; Standard deviation: 0.07; Accuracy score: 91 Mainstream
  13. OpenSpeedTest™ 53.21, 53.19 and 53.35; Average: 53.3; Median: 53.21; Standard deviation: 0.09; Accuracy score: 20
  14. RCN nowadays Astound 48, 48 and 47; Average: 48; Median: 48; Standard deviation: 0.6; Accuracy score: 20
  15. Samknows 51.4, 51.4 and 50.4; Average: 51.1; Median: 51.4; Standard deviation: 0.58; Accuracy score: 93 Mainstream
  16. SpeedOf.me 55.13, 54.97 and 55.01; Average: 55.0; Median: 55.01; Standard deviation: 0.08; Accuracy score: 93 Realistic
  17. SpeedSmart 54.48, 54.31 and 54.51; Average: 54.4; Median: 54.51; Standard deviation: 0.11; Accuracy score: 80 Realistic
  18. Speedtest 51.29, 50.76 and 50.80; Average: 51.0; Median: 50.80; Standard deviation: 0.30; Accuracy score: 99 Mainstream
  19. Speedtest4.php 234, 243 and 286; Average: 254; Median: 243; Standard deviation: 27.8; Accuracy score: 20
  20. TestMy.net 50.8, 50.6 and 51.1; Average: 50.8; Median: 50.8; Standard deviation: 0.25; Accuracy score: 99 Mainstream
  21. TheInternetSpeedTest.com (Gone) 54.30, 54.32 and 54.31; Average: 54.3; Median: 54.31; Standard deviation: 0.01; Accuracy score: 70
  22. Toast 36.7, 45.9 and 46.4; Average: 43.0; Median: 45.9; Standard deviation: 5.46; Accuracy score: 20
  23. Wi-Fi Speed Test (Gone) 54.39, 54.22 and 54.41; Average: 54.3; Median: 54.39; Standard deviation: 0.10; Accuracy score: 75
  24. Xfinity Speed Test 51.9, 51.6 and 52.1; Average: 51.9; Median: 51.9; Standard deviation: 0.25; Accuracy score: 79
 

Conclusions

Based on the these measurements we conclude the following:

  1. There are 6 speed tests which give an downloadspeed in the range 54-56 Mbps
    1. There are 3 realistic speed tests (Range 54.5 .. 56.0 Mbps)
  2. There are 10 speed tests which give an downloadspeed in the range 50-52 Mbps
    1. There are 9 mainstream speed tests (Range 50.0 .. 51.5 Mbps)
  3. There is 1 speed test which give an downloadspeed in the range 50-56 Mbps (actually 50-100 Mbps)
  4. Almost every speed test has a false accuracy

Our assumption that the ISP in use delivers a download speed of 56 Mbps, while 50 Mbps must be delivered contractually seems to be correct.

Speed test results in a graph

To make clear what the differences in measurements are, we have created the graph below.

Speed test results for a 50Mbps connection in a min avg max diagram

False accuracy

Almost every speed test has a false accuracy. The significant figures do not correspond to the standard deviation.

The only exception is "Internet Speed at a Glance" which only gives a range for the download speed.