Why hex is used for colors and memory

Hexadecimal shows up everywhere a computer exposes its raw bytes: color codes like #FF8800, memory addresses like 0x7ffe, MAC addresses, hash digests, and hex dumps. It is not that computers think in base 16. The reason is a single tidy fact about how hex lines up with binary, and once you see it the choice stops looking arbitrary.

One hex digit is four bits

A hexadecimal digit ranges over 16 values, 0 through F. Sixteen is 2 to the 4th power, so one hex digit encodes exactly four binary bits, with no remainder and no overlap:

0 = 0000      4 = 0100      8 = 1000      C = 1100
1 = 0001      5 = 0101      9 = 1001      D = 1101
2 = 0010      6 = 0110      A = 1010      E = 1110
3 = 0011      7 = 0111      B = 1011      F = 1111

Because the fit is exact, you can convert between binary and hex by grouping bits into fours and translating each group on its own, in either direction, with no arithmetic that crosses group boundaries. Decimal has no such property: 10 is not a power of 2, so a decimal digit smears across a messy number of bits and tells you nothing clean about the underlying binary.

So a byte is always two hex digits

A byte is 8 bits. Eight bits is two groups of four, so a byte is always exactly two hex digits, from 00 to FF, covering all 256 possible values:

1111 1011  =  F B  =  0xFB  =  251

This two digits per byte rule is the whole reason hex feels natural for low level work. A four byte value is eight hex digits, a sixteen byte hash is thirty two, and the boundaries never drift. You can glance at a hex dump and know instantly how many bytes you are looking at.

Why colors use it

A standard web color is three bytes: one each for red, green, and blue, each from 0 to 255. Written in hex that is #RRGGBB, two digits per channel, six digits total:

#FF8800  ->  R = FF (255)   G = 88 (136)   B = 00 (0)

Each pair maps directly onto one color byte, so #FF0000 is full red and #000000 is black with no mental conversion needed. The shorthand #F80 expands by doubling each digit, and an optional fourth pair adds an alpha byte. The same logic applies to memory addresses and MAC addresses: they are byte sequences, and hex is the shortest notation that keeps each byte visible as a clean pair.

Reading values both ways

When you need to move between a color's hex code and its decimal channels, or between a hex address and its binary, the base converter does it in your browser, so nothing you paste is transmitted. For color specific work, pairing it with converting HEX, RGB, and HSL colors covers the full set of formats.

The rule worth keeping: four bits per hex digit, two hex digits per byte. That exact alignment is why hex, not decimal, is the notation of choice whenever you are looking at the actual bytes a machine stores. For the mechanics of converting, see converting between binary, hex, and decimal.