Bandwidth and Latency

Learning Objectives

  • be able to explain the difference between bandwidth and latency.

Learning Outcomes

Must – understand that bandwidth and latency has an impact on downloads.

Should – be able to recognise the difference between fast and slow latency and high and low bandwidth.

Could – discuss the importance of having a fast download and upload speed.

What is the importance of Bandwidth and Latency?

Using a network connection involves transferring bits (1s and 0s) between 2 devices.  Network performance is how well that network can transfer the bits.  Bandwidth and Latency are two measurements to describe the performance of a network connection.


Bandwidth is the measurement of capacity on a network.

Bandwidth is the number of bits that can go through the network connection in 1 second.  It is measured in bits per second (bps).  Example:

1Kbps = 1 thousand bits can be transmitted every second

1Mbps = 1 million bits can be transmitted every second.

High Bandwidth = Good

Low Bandwidth = Bad


Latency is the measurement of delay.

Latency is the time in milliseconds between a bit leaving on the device and arriving at another device.  It is measured in milliseconds (ms).  The lower the time the quicker the download.

Low Latency = Good (Fast)

High Latency = Bad (Slow)

For a user

A person who has High Bandwidth and Low Latency has a good network connection and will be a satisfied user.  On the flip side, a Low Bandwidth and High latency network connection will cause frustration and dissatisfaction.


This is a topic which trips lots of people up in the final examination.  Write a set of clear revision notes with a detailed example where possible so you understand what Bandwidth and Latency mean, and also the difference between good and bad Bandwidth and Latency.