Number Base Converter
Type a number in any field and see it instantly in binary, octal, decimal, hexadecimal and a custom base from 2 to 36.
How to convert between number bases
- Type a number into any field: binary, octal, decimal, hexadecimal or your own base.
- All other fields fill in instantly. Prefixes like 0x, 0b and 0o are accepted, as are spaces and underscores.
- Check the bit count, byte count and character below the result.
Features
Five bases at once
Binary, octal, decimal, hex and any base from 2 to 36.
Arbitrarily large
Uses big integers, so there is no 53-bit limit.
Developer details
Bit length, byte count and the matching character.
Private
Conversion runs in your browser; nothing is uploaded.
Frequently asked questions
How do I convert binary to decimal?
Each binary digit is a power of two, starting from 1 on the right. 1101 is 8 + 4 + 0 + 1 = 13. Type it into the Binary field and the Decimal field shows the answer.
How does hexadecimal work?
Hex is base 16, using the digits 0–9 and A–F, where A is 10 and F is 15. Each hex digit equals exactly four binary digits, which is why it is popular for colours, memory addresses and bytes.
Does it support negative or huge numbers?
Yes. A leading minus sign is supported, and numbers of any length are handled exactly using JavaScript BigInt.
What is the highest custom base?
Base 36, which uses the digits 0–9 and the letters A–Z. Higher bases would need more symbols than letters and digits provide.