What are bits, bytes, and other units of measure for digital information?

Many hard drive manufacturers use a decimal number system to define amounts of storage space. As a result, 1MB is defined as one million bytes, 1GB is defined as one billion bytes, and so on. Since your computer uses a binary system as mentioned above, you may notice a discrepancy between your hard drive's published capacity and the capacity acknowledged by your computer. For example, a hard drive that is said to contain 10GB of storage space using a decimal system is actually capable of storing 10,000,000,000 bytes. However, in a binary system, 10GB is 10,737,418,240 bytes. As a result, instead of acknowledging 10GB, your computer will acknowledge 9.31GB. This is not a malfunction but a matter of different definitions.

We count in base 10 by powers of 10:

10¹ = 10 10² = 10*10 = 100 10³ = 10*10*10 = 1,000 10⁶ = 1,000,000

Computers count by base 2:

2¹ = 2 2² = 2*2 = 4 2³ = 2*2*2 = 8 2¹⁰ = 1,024 2²⁰ = 1,048,576

So in computer jargon, the following units are used:

Note: The names and abbreviations for numbers of bytes are easily confused with the notations for bits. The abbreviations for numbers of bits use a lower-case "b" instead of an upper-case "B". Since one byte is made up of eight bits, this difference can be significant. For example, if a broadband Internet connection is advertised with a download speed of 3.0Mbps, its speed is 3.0 megabits per second, or 0.375 megabytes per second (which would be abbreviated as 0.375MBps). Bits and bit rates (bits over time, as in bits per second [bps]) are most commonly used to describe connection speeds, so pay particular attention when comparing Internet connection providers and services.