Accuracy test 2025 (125 Mbps)

TL;DR

With an advertised download speed of 125 Mbps, it's best to use the Real Speed speed test. Real Speed is both highly accurate and extremely consistent.

SpeedSmart and Google Fiber are slightly less consistent, but also score well.

More consistent than SpeedSmart and Google Fiber are Samknows and Bredbandskollen.

 

Contents

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

Introduction

Every now and then we run a simple accuracy test.

Our internet provider offers a download speed of 125 Mbps. This means the to be measured speed is 126 Mbps (or 140 Mbps).

 

Method of measurement

For this test we test each speed test once and calculate the accuracy score based on that.

 

Speed tests to test

Because this is a relative simple test, all speed test used in earlier tests will be tested.

 

The measurements

  1. Real Speed 126 Mbps (Accuracy score: 100) Mainstream Tip
  2. Bing's Internet speed test 125.89 Mbps (Accuracy score: 100) Mainstream PopSpeedtest
  3. MySpeedCheck.net 126.3 Mbps (Accuracy score: 100) Mainstream Speedtest
  4. Optimum 126.5 Mbps (Accuracy score: 99) Mainstream Speedtest
  5. Frontier Internet Speed Test Tool 125.6 Mbps (Accuracy score: 99) Mainstream Speedtest
  6. Tiscali Italia 126.7 Mbps (Accuracy score: 99) Mainstream Speedtest
  7. Bredbandskollen 125.25 Mbps (Accuracy score: 99) Mainstream
  8. Speakeasy 125.2 Mbps (Accuracy score: 99) Mainstream Speedtest
  9. OpenSpeedTest™ 125.18 Mbps (Accuracy score: 99) Mainstream
  10. SpeedOf.me 139.07 Mbps (Accuracy score: 99) Realistic Pop
  11. Speedtest by Ookla 125.1 Mbps (Accuracy score: 99) Mainstream Pop
  12. WiFiman 141 Mbps (Accuracy score: 99)
  13. Samknows 127 Mbps (Accuracy score: 99) Mainstream
  14. AT&T 125 Mbps (Accuracy score: 98) Mainstream Speedtest
  15. SpeedSmart 127.2 Mbps (Accuracy score: 98) Mainstream
  16. PCMag 127.4 Mbps (Accuracy score: 98) Mainstream Speedtest
  17. CIRA's Internet Performance Test 124.48 Mbps (Accuracy score: 97) M-Lab
  18. TestMy.net 124.3 Mbps (Accuracy score: 97) Tip
  19. MyCCI 128.0 Mbps (Accuracy score: 96) Mainstream Speedtest
  20. Think Broadband (the standalone version) 124 Mbps (Accuracy score: 96)
  21. IPv6 - HTML5 Speedtest 127.93 Mbps (Accuracy score: 96) Mainstream LibreSpeed
  22. Fusion Connect 124.1 Mbps (Accuracy score: 96) Speedtest
  23. nPerf 123.8 Mbps (Accuracy score: 95)
  24. M-Lab 122.84 (NDT)/123.55 (MSAK) Mbps (Accuracy score: 87/93) Tip
  25. Waveform (Bufferbloat and Internet) speed test 123.5 Mbps (Accuracy score: 93)
  26. Cloudflare 123 Mbps (Accuracy score: 89) Pop
  27. RealSpeeds 123 Mbps (Accuracy score: 89) M-Lab
  28. Down at a Glance 123 Mbps (Accuracy score: 89) Tip M-Lab
  29. GCI 122.9 Mbps (Accuracy score: 88) Speedtest
  30. WhistleOut (Australia) 122.8 Mbps (Accuracy score: 87) M-Lab
  31. Broadband Genie 122.7 Mbps (Accuracy score: 86)
  32. Google Fiber (Ookla) speed test 122.3 Mbps (Accuracy score: 80) Speedtest
  33. U Switch 122 Mbps (Accuracy score: 75)
  34. Gcore 130.34 Mbps (Accuracy score: 68)
  35. MySpeedMeter 121.5 (ipv4, London) Mbps (Accuracy score: 64) Speedtest
  36. True Speed at a Glance 135 Mbps (Accuracy score: 48) Tip M-Lab
  37. Comcast Business Internet Speed Test 145 Mbps (Accuracy score: 48)
  38. Meter.net 120.7 Mbps (Accuracy score: 36)
  39. Broadband Speed Checker 120.50 Mbps (Accuracy score: 26)
  40. Google's Internet speed test 120.4 Mbps (Accuracy score: 21) Pop M-Lab
  41. Internet Speed at a Glance 100..200 Mbps (Accuracy score: 20)
  42. IPv4 - HTML5 Speedtest 133.47 Mbps (Accuracy score: 20) LibreSpeed
  43. LibreSpeed 133 Mbps (Accuracy score: 20)
  44. IPv4 / IPv6 - HTML5 Speedtest 131.17 Mbps (Accuracy score: 20) LibreSpeed
  45. Breezeline 120.3 Mbps (Accuracy score: 20)
  46. Xfinity Speed Test 120.1 Mbps (Accuracy score: 20)
  47. HighSpeedInternet 118.27 Mbps (Accuracy score: 20)
  48. Fireprobe 117.86 Mbps (Accuracy score: 20)
  49. Speedtest.co.za 116.59 Mbps (Accuracy score: 20)
  50. IPv6 Test 116 (ipv4)/111 (ipv6) Mbps (Accuracy score: 20)
  51. Bandwidth Place 114.87 Mbps (Accuracy score: 20) M-Lab
  52. Interprefy 114.8 Mbps (Accuracy score: 20)
  53. MyBroadband 112.06 Mbps (Accuracy score: 20)
  54. Google Fiber 112 Mbps (Accuracy score: 20) Tip
  55. Fast 110 Mbps (Accuracy score: 20) Pop
  56. Verizon 108 Mbps (Accuracy score: 20)
  57. Astound 106.00 Mbps (Accuracy score: 20)
  58. CenturyLink 102 Mbps (Accuracy score: 20)
  59. SG Speed Test 95.14 Mbps (Accuracy score: 20)
  60. Which Broadband Checker 163 Mbps (Accuracy score: 20)
  61. myspeed.ai 89.4 Mbps (Accuracy score: 20)
  62. Simple Speed Test Online 48.53 Mbps (Accuracy score: 20)
  63. Speedtest4.php 298 Mbps (Accuracy score: 20)
  64. Comparitech No results (Accuracy score: 0)
  65. Cox Request blocked (Accuracy score: 0)
  66. Speedcheck™ No results (Accuracy score: 0)
 

First conclusions

There are:

  1. 16 mainstream speed tests
  2. 32 speed tests with an accuracy score of 75 or higher
  3. 9 Speedtest clones

We repeat this test for a select number of speed tests (Tip, Pop, a high accuracy score, mentioned in Which speed tests to test, but not for all Speedtest clones). This time, however, we test five times and calculate the median, the standard deviation and the accuracy score.

  1. Google Fiber 126, 124, 126, 118 and 128 Mbps (Median: 126 Mbps, standard deviation 3.85 Mbps, accuracy score: 100) Mainstream Tip
  2. Real Speed 126, 126, 126, 126 and 126 Mbps (Median: 126 Mbps, standard deviation 0 Mbps, accuracy score: 100) Mainstream Tip
  3. SpeedSmart 128.0, 126.0, 124.0, 125.8 and 126.8 Mbps (Median: 126.0 Mbps, standard deviation 1.47 Mbps, accuracy score: 100) Mainstream
  4. Bredbandskollen 127.20, 126.89, 127,07, 127.75 and 126.36 Mbps (Median: 127.07 Mbps, standard deviation 0.50 Mbps, accuracy score: 99) Mainstream
  5. Samknows 127, 126, 127, 127 and 127 Mbps (Median: 127 Mbps, standard deviation 0.45 Mbps, accuracy score: 99) Mainstream
  6. Speedtest by Ookla 128.22, 126.86, 114.22, 128.00 and 126.63 Mbps (Median: 126.86 Mbps, standard deviation 5.95 Mbps, accuracy score: 99) Mainstream Pop
  7. SpeedOf.me 138.22, 136.69, 138.14, 138.17 and 137.23 Mbps (Median: 138.14 Mbps, standard deviation 3.33 Mbps, accuracy score: 96) Realistic Pop
  8. Think Broadband (the standalone version) 123, 126, 124, 124 and 124 Mbps (Median: 124 Mbps, standard deviation 1.10 Mbps, accuracy score: 96)
  9. Bing's Internet speed test 123.28, 127.36, 123.80, 127.31 and 118.39 Mbps (Median: 123.80 Mbps, standard deviation 3.68 Mbps, accuracy score: 95) Pop Speedtest
  10. Fireprobe 124.72, 115.15, 124.71, 117.58 and 123.95 Mbps (Median: 123.95 Mbps, standard deviation 4.53 Mbps, accuracy score: 95)
  11. nPerf 128.0, 128.4, 128.4, 128.4 and 128.3 Mbps (Median: 128.4 Mbps, standard deviation 0.17 Mbps, accuracy score: 93) Mainstream
  12. OpenSpeedTest™ 129.33, 128.50, 128.87, 130.49 and 127.06 Mbps (Median: 128.87 Mbps, standard deviation 1.25 Mbps, accuracy score: 90) Mainstream
  13. M-Lab (MSAK) 122.80, 122.00, 122.48, 124.26 and 106.36 Mbps (Median: 122.48 Mbps, standard deviation 7.44 Mbps, accuracy score: 83) Tip
  14. M-Lab (NDT) 119.59, 122.07, 123.09, 123.71 and 122.07 Mbps (Median: 122.07 Mbps, standard deviation 1.57 Mbps, accuracy score: 76) Tip
  15. Down at a Glance 122, 115, 121, 121 and 119 Mbps (Median: 121 Mbps, standard deviation 2.79 Mbps, accuracy score: 48) Tip M-Lab
  16. LibreSpeed 135, 134, 135, 135 and 135 Mbps (Median: 135 Mbps, standard deviation 0.45 Mbps, accuracy score: 48)
  17. True Speed at a Glance 134, 137, 134, 136 and 135 Mbps (Median: 135 Mbps, standard deviation 1.30 Mbps, accuracy score: 48) Tip M-Lab
  18. WiFiman 130.35, 136.88, 132.82, 135.04 and 134.65 Mbps (Median: 134.65 Mbps, standard deviation 2.47 Mbps, accuracy score: 33)
  19. CIRA's Internet Performance Test 86.85, 121.01, 107.06, 121.40 and 99.25 Mbps (Median: 107.06 Mbps, standard deviation 14.75 Mbps, accuracy score: 20) M-Lab
  20. TestMy.net 121.6, 118.6, 117.8, 120.2 and 114.4 Mbps (Median: 118.6 Mbps, standard deviation 2.73 Mbps, accuracy score: 20) Tip
  21. IPv6 - HTML5 Speedtest 133.02, 132.74, 132.93, 133.23 and 131.75 Mbps (Median: 132.93 Mbps, standard deviation 0.58 Mbps, accuracy score: 20) LibreSpeed
  22. Waveform (Bufferbloat and Internet) speed test 117.4, 124.6, 119.2, 128.8 and 104.2 Mbps (Median: 119.2 Mbps, standard deviation 9.34 Mbps, accuracy score: 20)
  23. Cloudflare 115, 115, 122, 121 and 120 Mbps (Median: 120 Mbps, standard deviation 3.36 Mbps, accuracy score: 20) Pop
  24. Google's Internet speed test 113.7, 122.0, 118.9, 118.4 and 122.9 Mbps (Median: 118.9 Mbps, standard deviation 3.62 Mbps, accuracy score: 20) Pop M-Lab
  25. Internet Speed at a Glance 100..200, 50..100, 100..200, 100..200 and 50..100 Mbps (Median: 100..200 Mbps, standard deviation 50 Mbps, accuracy score: 20) Tip
  26. Fast 110, 120, 110, 100 and 110 Mbps (Median: 110 Mbps, standard deviation 7.07 Mbps, accuracy score: 20) Pop
  27. Comparitech No results at all
  28. Xfinity Speed Test 112.4, 115.1, 119.5, 123.8 and 123.7 Mbps (Median: 119.5 Mbps, standard deviation 5.10 Mbps, accuracy score: 20)
  29. Meter.net 123.8, 120.2, 109.1, 119.0 and 121.1 Mbps (Median: 120.2 Mbps, standard deviation 5.62 Mbps, accuracy score: 20)
  30. Bandwidth Place 120.02, 119.27, 119.49, 118.08 and 121.35 Mbps (Median: 119.49 Mbps, standard deviation 1.19 Mbps, accuracy score: 20) M-Lab
 

Conclusions

The most accurate speed tests (accuracy score 100!), with a download speed of 125 Mbps, are:

  1. Real Speed
  2. SpeedSmart
  3. Google Fiber

If we were to sort by standard deviation, the top 3 would look like this:

  1. Real Speed
  2. Samknows
  3. Bredbandskollen

The Real Speed speed test has a standard deviation of zero. Hence this is the best speed test for this download speed.