Number Base Converter Online (Binary, Octal, Decimal, Hex) — Free
Runs 100% in your browser — your files never leave your device.
Bitmasks, color channels, memory addresses, permission flags — the daily traffic between decimal and hex. Type a number, pick the source and target bases, and get the conversion instantly, computed with arbitrary precision so values past 2⁵³ stay exact. Swap the direction with one click.
How it works
- 1
Type a number
Digits valid for the source base — hex letters in either case.
- 2
Pick the bases
Binary, octal, decimal, hexadecimal — swap direction any time.
- 3
Copy the result
The converted value appears live; one click copies it.
About this tool
What base conversion means
Numbers have no base — only their representations do. The tool converts an integer between base 2 (binary), 8 (octal), 10 (decimal), and 16 (hexadecimal), and any custom base up to 36. The value is identical; only the notation changes.
Where each base lives
Binary is machine memory and permissions, hex is colors, memory addresses, and hashes, octal is file permissions and old systems, decimal is everywhere human. Developers cross these daily — the conversion is exact in both directions, with BigInt precision for very large values.
Reading the conversions back
Hex digits A–F stand for 10–15, and each hex digit is exactly four binary digits — which is why hex is the human shorthand for binary. Check yourself: F in hex is 15 in decimal is 1111 in binary, always.
Frequently asked questions
Can it convert very large numbers?
Yes — conversion uses arbitrary-precision arithmetic, so values beyond the normal integer range convert exactly rather than losing digits.
What bases are supported?
Binary, octal, decimal, hexadecimal, and any custom base from 2 to 36 — digits beyond 9 continue through the alphabet.
Does it handle negative numbers?
Yes — the sign carries through and the magnitude converts exactly.