Accuracy check

How accurate are speed tests?

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

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

In a graph these are the test results:

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

There are 6 speed tests which give an downloadspeed in the range 54-56Mbps.

There are 10 speed tests which give an downloadspeed in the range 50-52Mbps.

There is 1 speed test which give an downloadspeed in the range 50-56Mbps (actually 50-100Mbps).

Detailed results per speed test

Bandwidth Place

  1. 46,96Mbps
  2. 46,24Mbps
  3. 46,19Mbps

That gives an average of 46,5Mbps and a standard deviation of 0.43Mbps for the downloadspeed.

Broadband Speed Checker

  1. 48,30Mbps
  2. 50,78Mbps
  3. 51,17Mbps

That gives an average of 50,4Mbps and a standard deviation of 0.99Mbps for the downloadspeed.

Cloudfare

  1. 45,9Mbps
  2. 48,0Mbps
  3. 47,7Mbps

That gives an average of 47,2Mbps and a standard deviation of 1,14Mbps for the downloadspeed.

Comparitech

  1. 55,31Mbps
  2. 55,25Mbps
  3. 54,61Mbps

That gives an average of 55.1Mbps and a standard deviation of 0.39Mbps for the downloadspeed.

DSLReports

  1. 51,8Mbps
  2. 50,3Mbps
  3. 50,7Mbps

That gives an average of 50,9Mbps and a standard deviation of 0.78Mbps for the downloadspeed.

Fast

  1. 46Mbps
  2. 42Mbps
  3. 45Mbps

That gives an average of 44Mbps and a standard deviation of 2.1Mbps for the downloadspeed.

Fireprobe

  1. 51.40Mbps
  2. 51.24Mbps
  3. 50.21Mbps

That gives an average of 51.0Mbps and a standard deviation of 0.65Mbps for the downloadspeed.

Google Fiber

  1. 51.1Mbps
  2. 51.3Mbps
  3. 51.7Mbps

That gives an average of 51.4Mbps and a standard deviation of 0.31Mbps for the downloadspeed.

Internet Speed at a Glance

  1. 50..100Mbps
  2. 50..100Mbps
  3. 50..100Mbps

LibreSpeed

  1. 54.1Mbps
  2. 54.3Mbps
  3. 54.4Mbps

That gives an average of 54.3Mbps and a standard deviation of 0.15Mbps for the downloadspeed.

Measurement Lab

  1. 50.82Mbps
  2. 51.13Mbps
  3. 51.17Mbps

That gives an average of 51.0Mbps and a standard deviation of 0.19Mbps for the downloadspeed.

N Perf Internet speed test

  1. 51.49Mbps
  2. 51.59bps
  3. 51.45bps

That gives an average of 51.5Mbps and a standard deviation of 0.07Mbps for the downloadspeed.

Ookla Speedtest

  1. 51.29Mbps
  2. 50.76Mbps
  3. 50.80Mbps

That gives an average of 51.0Mbps and a standard deviation of 0.30Mbps for the downloadspeed.

Open Speed Test

  1. 53.21Mbps
  2. 53.19Mbps
  3. 53.35Mbps

That gives an average of 53.3Mbps and a standard deviation of 0.09Mbps for the downloadspeed.

RCN Speedtest

  1. 48Mbps
  2. 48Mbps
  3. 47Mbps

That gives an average of 48Mbps and a standard deviation of 0.6Mbps for the downloadspeed.

Sam Knows

  1. 51.4Mbps
  2. 51.4Mbps
  3. 50.4Mbps

That gives an average of 51.1Mbps and a standard deviation of 0.58Mbps for the downloadspeed.

Speed Of Me

  1. 55.13Mbps
  2. 54.97Mbps
  3. 55.01Mbps

That gives an average of 55.0Mbps and a standard deviation of 0.08Mbps for the downloadspeed.

SpeedSmart

  1. 54.48Mbps
  2. 54.31Mbps
  3. 54.51Mbps

That gives an average of 54.4Mbps and a standard deviation of 0.11Mbps for the downloadspeed.

Speedtest4.php

  1. 234Mbps
  2. 243Mbps
  3. 286Mbps

That gives an average of 254Mbps and a standard deviation of 27.8Mbps for the downloadspeed.

TestMy.net

  1. 50.8Mbps
  2. 50.6Mbps
  3. 51.1Mbps

That gives an average of 50.8Mbps and a standard deviation of 0.25Mbps for the downloadspeed.

TheInternetSpeedTest.com

  1. 54.30Mbps
  2. 54.32bps
  3. 54.31Mbps

That gives an average of 54.3Mbps and a standard deviation of 0.01Mbps for the downloadspeed.

Toast Internet Speed Test

  1. 36.7Mbps
  2. 45.9Mbps
  3. 46.4Mbps

That gives an average of 43.0Mbps and a standard deviation of 5.46Mbps for the downloadspeed.

Wi-Fi Speed Test

  1. 54.39Mbps
  2. 54.22bps
  3. 54.41Mbps

That gives an average of 54.3Mbps and a standard deviation of 0.10Mbps for the downloadspeed.

Xfinity xFi Speed Test

  1. 51.9Mbps
  2. 51.6Mbps
  3. 52.1Mbps

That gives an average of 51.9Mbps and a standard deviation of 0.25Mbps for the downloadspeed.

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.