Number Base Converter
Enter a number in any base — the rest recalculate instantly. Binary, octal, decimal, hexadecimal. Plus bit representation and 0–15 reference table.
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Converter
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Reference table 0–15
clicking a row loads its decimal value into the converter0–15 covers every possible value of a single nibble (4 bits) and a single HEX digit.
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About numeral systems
A numeral system defines how many digits are used to write a number. Decimal uses 10 digits (0–9) — the everyday base. Binary uses just 0 and 1 — the language of hardware.
They all represent the same number — just with different symbols. 255 in decimal = FF in HEX = 11111111 in BIN = 377 in OCT.
Binary (base 2)
Hardware10 → 1010 · 255 → 11111111
Uses only 0 and 1 — the physical state of a transistor: off / on. Processors, memory, and data buses all operate in binary. Every other system is a human-friendly layer on top.
Octal (base 8)
Unix perms8 → 10 · 511 → 777
Each digit encodes exactly 3 bits. Used in Unix for file permissions: chmod 755 = rwxr-xr-x, where each group of 3 bits covers owner, group, and others.
Hexadecimal (base 16)
Code & colors255 → FF · 4096 → 1000
Each HEX digit encodes exactly 4 bits (a nibble), two chars = one byte. Ideal for memory addresses, MAC addresses, #RRGGBB colors, SHA/MD5 hashes, and bytecode.
Where each is used
BIN → CPU · OCT → chmod · HEX → colors
Binary — machine code, bit flags, masks. Octal — Unix file permissions, some configs. HEX — CSS colors, memory addresses, debuggers, UUIDs, hashes.