# Binary and Decimal Prefixes

### Decimal Prefixes – Kilo / Mega / Giga  / Tera

The most common prefix system used is the Decimal Prefix system. This is the system we use every day: Kilogram, Megabyte, Kilometer

The decimal prefix system works by each prefix being 1000 times larger than the previous prefix:

• 1 KiloByte = 1000Bytes          (10^3)
• 1 MegaByte = 1000 KiloBytes = 1,000,000 Bytes   ( 10^6)
• 1 GigaByte = 1000 MegaBytes = 1,000,000,000 Bytes  ( 10^9)
• 1 TeraByte = 1000 GigaBytes = 1,000,000,000,000 Bytes  ( 10^12)

### Binary Prefixes – Kibi / Mebi  / Gibi / Tebi

This works well where we humans count in denary (Powers of 10) but computers count in binary (Powers of 2) and therefore we need to use a binary prefix instead – Kibi, Mebi, Gibi, Tebi

• 1 KiB = 1024 Bytes   ( 2 ^10)
• 1 MiB = 1024 KiB ( 2^20)
• 1 GiB = 1024 MiB ( 2^30)
• 1 TiB = 1024 GiB ( 2^40)

### Consumer Confusion Nightmare.

Consumers are used to using kilo, mega, giga, etc. This meant that when personal computers became popular manufacturers of software and hardware began to use the system inconsistently (KB could mean either 1000 or 1024 bytes). There was an attempt to fixing this through the implementation of the IEC standard, however Microsoft being Microsoft refused to adopt international standards, stating (just like they did with IE until everyone stopped using it). Apple’s iOS and some versions of Linux follow the international standard.

Teacher Resources

Binary and Decimal Prefixes Presentation

Binary and Decimal Prefixes Worksheet