Number Base Converter
Convert between decimal, binary, hexadecimal, octal and any base up to 36.
—————💡 Click any result row to use it as a new input. All conversions are instant and client-side.
About the Number Base Converter
This converter shows binary, octal, decimal, hexadecimal and base 36 representations at once rather than one conversion at a time. Type a value in whichever base you happen to have and the others update immediately, with 8, 16 and 32-bit range indicators — which is what makes it useful while debugging a register or bitmask.
A binary, hex, decimal and octal converter covers the four bases programming actually uses. Hex appears in colour codes, memory addresses and byte values; binary in bit masks and flags; octal in Unix permissions; decimal everywhere else.
Showing all four simultaneously is the point. When you are reading a register value or a bitmask, the useful question is usually "which bits does 0x2C set" — and that requires seeing hex and binary side by side rather than converting one at a time.
The relationships are worth internalising: one hex digit is exactly four binary digits, and one octal digit is exactly three. That is why hex is the compact way to write binary, and why chmod values are octal — three permission bits per digit.
How to use the Number Base Converter
- Type a value. Enter the number in whichever base you have.
- Read the others. Binary, octal, decimal and hex all update together.
- Check the bits. Compare the hex and binary forms to see which bits are set.
- Copy what you need. Take the representation you want.
Number Base Converter features
- Binary, octal, decimal, hexadecimal and base 36
- All representations shown at once
- 8, 16 and 32-bit range indicators
- Updates as you type, from whichever base you enter
- Copy any representation
Frequently asked questions
Which bases are shown?
Base 2, 8, 10 and 16 — the four that matter in programming — plus base 36, which uses the digits and the whole alphabet to write numbers as compactly as possible.
What are the bit-range indicators for?
They show whether your value still fits in 8, 16 or 32 bits. That is the check you want when writing to a register or a fixed-width field, where overflow is silent and the symptom appears much later.
Why is hexadecimal used so widely?
Because one hex digit is exactly four bits, so a byte is always two hex digits and the mapping to binary is trivial. It gives you binary's structure without binary's length.
Why does octal still exist?
Almost entirely for Unix file permissions, where three bits per digit lines up with read, write and execute. Outside that it is a historical curiosity.
Does it handle negative numbers?
It converts the magnitude you enter. Negative values in fixed-width contexts are represented as two's complement, which the bitwise calculator is the better tool for exploring.