ADSL - Test the speed of your internet connection

December 2016

Download speeds (theoretical approach)

Types of connections

The list below gives the correspondence between the speed (bandwidth) expressed in bits per second and throughput :
  • 56K = 7 Kbps
  • 128 K = 16 Kbps
  • 512 K = 64 Kbps
  • 1024 K = 128 Kbps
  • 2048 K = 256 Kbps

56 kbit/s (56,000 bits per second)

Why there's a difference?

Byte is the translation of byte (not bit).
  • 1 byte = 8 bits
  • 56 Kbps = 56/8 Kbps= 7 KBps
  • 128 Kbps = 128/8 Kbps = 16 KBps
  • 512 Kbps = 512/8 Kbps = 64 KBps
  • 1024 Kbps = 1024/8 Kbps= 128 KBps
  • 2048 Kbps = 2048/8 Kbps= 256 KBps

Note that: the speed varies from one ISP to another.

I have an ADSL xxxx, but when download data, its speed drops?

The speed of an ADSL line is the theoretical maximum throughput possible.

If the server where you're downloading is able to send you only 3 Kb/sec, you will receive 3 Kb/second, even if you are usin ADSL 8192. Your ISP is not the one responsible!
  • When connected to a LAN, the slowest computer defines the maximum speed!

The upload speed is too slow!

Upload speed does not exceed 64 Kb/second.
  • This is normal. ADSL = Asymmetric Digital Subscriber Line.
  • The "A" in ADSL means that the connection is asymmetric: The download performance is important, but the upstream (upload) is lower.


Test the speed of your ADSL

The tests results can be altered if you are downloading data or making use a VoIP phone at the same time, its better to avoid making use of your Internet connection during the testing phase.

Other Links

  • Binary encoding
  • ADSL

Related :

This document entitled « ADSL - Test the speed of your internet connection » from CCM ( is made available under the Creative Commons license. You can copy, modify copies of this page, under the conditions stipulated by the license, as this note appears clearly.