Reading a hex value from a stack trace and figuring out what it is in decimal. Converting CSS colour 0xff8800 into an RGB triple, or vice versa. Inspecting a bitmask or flags integer in binary to see which bits are set. Translating between base-36 short IDs and decimal counters.

Hex: 0x , 0X , # Binary: 0b , 0B Octal: 0o , 0O Underscore digit grouping: 1_000_000

Negative numbers are sign-prefixed, not two's complement. -128 is shown as -10000000 in binary, not 10000000 . Most languages display the same way for arbitrary-precision integers. Big numbers don't lose precision here. JavaScript Number caps at 2 53 ; this tool uses BigInt , so 64-bit integers, large hashes, and crypto values all round-trip exactly. Don't confuse base with case. Base-16 letters can be upper or lower; the tool accepts both and emits uppercase. Base-32 / base-36 outputs are lowercase by convention. Leading zeros are dropped. 0x000F becomes F . If you need a fixed-width hex (e.g. for byte representations), pad in your code afterward.

Convertisseur de Bases

Convertissez entre binaire, octal, décimal, hexadécimal et toute base de 2 à 36.

Entrée

De (base)

All bases

Base	Value
2 (binary)	`…`
8 (octal)	`…`
10 (decimal)	`…`
16 (hex)	`…`
32	`…`
36	`…`

What is this for?

Numbers are the same number regardless of base — 255, 0xff, 0b11111111, and 0o377 are identical. But which base you read or write in matters when you're translating between memory layouts, parsing colour codes, decoding bit fields, or just reading hex from a debugger. This tool converts between binary, octal, decimal, hexadecimal, and any base from 2 to 36, using BigInt under the hood so you don't lose precision on large numbers.

When to use it

Reading a hex value from a stack trace and figuring out what it is in decimal.
Converting CSS colour 0xff8800 into an RGB triple, or vice versa.
Inspecting a bitmask or flags integer in binary to see which bits are set.
Translating between base-36 short IDs and decimal counters.

Recognised prefixes

Hex: 0x, 0X, #
Binary: 0b, 0B
Octal: 0o, 0O
Underscore digit grouping: 1_000_000

Common gotchas

Negative numbers are sign-prefixed, not two's complement. -128 is shown as -10000000 in binary, not 10000000. Most languages display the same way for arbitrary-precision integers.
Big numbers don't lose precision here. JavaScript Number caps at 2⁵³; this tool uses BigInt, so 64-bit integers, large hashes, and crypto values all round-trip exactly.
Don't confuse base with case. Base-16 letters can be upper or lower; the tool accepts both and emits uppercase. Base-32 / base-36 outputs are lowercase by convention.
Leading zeros are dropped. 0x000F becomes F. If you need a fixed-width hex (e.g. for byte representations), pad in your code afterward.