What is Binary and Why Do Computers Use It?
Binary: Binary is a base-2 numeral system that uses only two digits , 0 and 1. Each digit is called a bit (short for binary digit).
Every single piece of data stored or processed by a computer , numbers, text, images, audio, video , is ultimately represented as a sequence of 1s and 0s. This isn't arbitrary: computers are built from billions of tiny electronic switches called transistors, which have exactly two states:
- On → 1
- Off → 0
Because the hardware naturally operates in two states, binary is the perfect fit. There's no ambiguity, no rounding , just on or off.
Binary is like a digital Morse code , only two symbols, but through different combinations, you can express anything from the letter 'A' to a full HD movie.
Binary is the most compact and reliable representation for computers because it directly mirrors the physical behaviour of transistors. More complex number systems would require hardware that distinguishes many voltage levels, which is far more error-prone.
Units of Binary Data
Binary data is measured in increasingly large units. Starting from the smallest:
| Unit | Size |
|---|---|
| 1 bit | 1 binary digit (0 or 1) |
| 1 nibble | 4 bits |
| 1 byte | 8 bits |
| 1 kilobyte (KB) | bytes |
| 1 megabyte (MB) | bytes |
| 1 gigabyte (GB) | bytes |
| 1 terabyte (TB) | bytes |
| 1 petabyte (PB) | bytes |
Note that in computing, 1 kilobyte = 1024 bytes (not 1000). This is because binary systems work in powers of 2, and . Don't confuse this with the SI (metric) prefix kilo = 1000, which is used in some storage marketing contexts.
A handy memory sequence: bit → nibble → byte → KB → MB → GB → TB → PB. Each step from KB onwards multiplies by 1024.