Binary, Hex, Octal Converter

Computers think in binary, programmers write in hex, old systems file permissions in octal, and humans usually mean decimal. Every conversion between these four systems is pure arithmetic - but doing it by hand past a dozen bits means long division, repeated squaring, and an excellent chance of dropping a digit somewhere. The relationships are simple: one hex digit is four bits, one octal digit is three.

Binary, Hex, Octal Converter converts any whole number among decimal, binary, hexadecimal and octal exactly, using BigInt arithmetic with no floating point anywhere. Bit counts, byte alignment and the digit groups are all shown. Paste a value in any base, get all four representations, and see how the systems mirror each other.

• Four bases, both directions: Decimal, binary, hex and octal.
• Exact BigInt arithmetic: Up to 1024 bits, no rounding ever.
• All representations at once: Every base shown from any input.
• Bit count and bytes: Size information included.
• Digit grouping: Hex and octal groups made visible.
• Instant conversion: Live as you type.
• Copy or download: Results ready for code and notes.
• Free and private: Everything runs in your browser; nothing is uploaded.

1. Enter a number in any base - include a prefix like 0b, 0x or 0o if you use one.
2. Read all four representations - decimal, binary, hexadecimal and octal.
3. Check the bit count and how the value aligns into bytes.
4. Study the grouping that connects the bases.
5. Copy or download the representation you need.

Example 1 - The classic. Enter binary 1101: decimal 13, hex D, octal 15 - with the bit count 4 shown.

Example 2 - Programmer constants. Enter 0xFF (255): binary 11111111, octal 377 - a byte, fully set.

Example 3 - Large values. Enter 4294967295 (the 32-bit maximum): hex FFFFFFFF, binary 32 ones - the tool shows why it is the max of a 32-bit unsigned integer.

Example 4 - Octal in. Enter 0o777: decimal 511, binary 111111111 - three octal digits, nine bits.

Example 5 - Hex shorthand. Enter hex CAFE: the binary representation 1100101011111110 and its nibble grouping are displayed side by side.

• Exact at any scale: BigInt arithmetic, no floating point.
• All four bases: Every input, every representation.
• Educational grouping: See why hex and octal exist.
• Size awareness: Bits and bytes for every value.
• Instant and live: No button presses, no waiting.
• Free and private: Runs entirely in the browser with nothing uploaded.