Measurements we use in everyday life, like metres and litres, have their counterparts in computer terminology.

This article seeks to describe them.

(Some measurements are commonly written lower/upper case, we have sought to maintain this)

dpi stands for dots per inch.

Its a measure of how fine the grain on the printing surface is.

So paper with a high dpi, will have a fine grain, and will show high resolution photos to best effect.

Quite what seperates matte from gloss, we don't know !

gsm stands for grams per square metre.

Sometimes also seen as g/m² or gm^-2

It is the measure of the thickness of paper.

The smallest unit of storage in a compuer is a bit

Bit stands for Binary digIT

A bit is either a 1 (one) or a 0 (zero)

A bit is stored on a hard drive (for example) by a tiny area being:
- Magnetized for a 1
- Not magnetized for a 0

A bit may travel through your computer by a wire being:
- 5 volts for a 1
- 0 volts for a 0

A byte is a collection of 8 bits

A kb (kilo-byte) is a collection of 1000 bytes

A MB (mega-byte) is a collection of 1000kb (or 1 million bytes)

A GB (giga-byte) is a collection of 1000MB (or 1000 million bytes)

A TB (tera-byte) is a collection of 1000GB (a million million bytes)


(Accurately speaking you should multiply by 1024 each time, not 1000. This is because of the way computers count)

The rate that data gets from one place to another is usually measured in bps

bps stands for bits per second

kbps (kilo-bps) = 1000 bits per second

Mbps (mega-bps) = 1 million bits per second


USB version 2 for example has a maximum datarate of 480Mbps

The speed of your Internet connection is usually measured in k or MB

512k means you can download 512 kilo-bytes of data per second

2MB means you can download 2 mega-bytes of data per second

As seen above kilo means 1000 times, mega means 1 million times.

They're all part of the metric (SI / Systeme Internationale) system.

Just for interest here are a few more:

P peta = a thousand million million
T tera = a million million
G giga = a thousand million
M mega = a million
k kilo = a thousand

m milli = 0.001
µ micro = 0.000 001
n nano = 0.000 000 001
p pico = 0.000 000 000 001
f femto = 0.000 000 000 000 001