UNDERSTANDING COMPUTER BITS AND BYTES

Below is a list of each of the accepted disk drive space values. It is important to realize that not all manufacturers and developers use binary base 2. For example, a manufacturer may consider a gigabyte as 1,000,000,000 bytes and not 1,073,741,824 bytes. All measurements in this article are listed in their base 2 values.

With the exception of a bit and a nibble, all values explained below are in bytes and not bits. For example, a Kilobyte (KB) is different than a Kilobit (Kb). When referring to storage, bytes are used, when referring to transmission speeds bits are used.

Bit

A bit is a value of either a 1 or 0 (on or off).

Nibble

A Nibble is 4 bits.

Byte

A Byte is 8 bits.

Kilobyte (KB)

A Kilobyte is 1,024 bytes.

Megabyte (MB)

A Megabyte is 1,024 Kilobytes.

Gigabyte (GB)

A Gigabyte is 1,024 Megabytes.

Terabyte (TB)

A Terabyte is 1,024 Gigabytes.

Petabyte (PB)

A Petabyte is 1,024 Terabytes

Exabyte (EB)

An Exabyte is 1,024 Petabytes

Zettabyte (ZB)

A Zettabyte is 1,024 Exabytes

Yottabyte (YB)

A Yottabyte is 1,024 Zettabytes

But why are there 1024 bytes in a kilobyte?

Many people think that there are 1000 bytes in a kilobyte. After all, "kilo" means 1000. In most cases, this approximation is fine for determining how much space a file takes up or how much disk space you have.

But there are really 1024 bytes in a kilobyte. The reason for this is because computers are based on the binary system. That means hard drives and memory are measured in powers of 2.

For example,

2⁰ = 1

2¹ = 2

2² = 4

2³ = 8

2⁴ = 16

2⁵ = 32

2⁶ = 64

2⁷ = 128

2⁸ = 256

2⁹ = 512

2¹⁰ = 1024

Notice that 2¹⁰ is 1024. Therefore, 1024 bytes compose one kilobyte. Furthermore, 1024 kilobytes compose one megabyte, and 1024 megabytes compose one gigabyte and so on. For practical purposes, you can estimate 1024 to 1000, but an in-depth understanding is what differentiates computer novices from gurus.

By Theophilus Amenger