Four bases at once
See binary, octal, decimal and hexadecimal update live as you type. Plus any custom base from 2 to 36.
Binary · Octal · Decimal · Hex · Any base 2–36 · No upload
Number Base Converter
Convert any number between binary, octal, decimal and hexadecimal at the same time. Pick any base from 2 to 36, work with negative numbers using two's complement, toggle individual bits, group digits, add prefixes and convert whole lists at once. Everything runs in your browser with BigInt precision.
Bit view — click a bit to flip it
One number per line
Result
Ready
Key features
BigInt precision
Handles arbitrarily large integers — well past 64 bits — with zero floating-point rounding errors.
Two's complement
Pick 8, 16, 32 or 64-bit width and negative numbers render as proper two's complement in binary and hex.
Bit toggling
Click individual bits to flip them and watch every base recompute. Great for learning and debugging masks.
Frequently asked questions
How do I convert binary to decimal here?
Set From base to Bin 2, then type or paste your binary digits. The decimal value appears instantly in the Decimal row, alongside octal and hexadecimal. Switch to Auto and prefix the value with 0b to mix bases freely.
What does "Auto" detect?
Auto reads the prefix: 0x = hex, 0o = octal, 0b = binary. With no prefix it assumes decimal, unless the value contains hex letters (a–f), in which case it reads it as hexadecimal.
Can it convert negative numbers?
Yes. In decimal you can type a leading -. With a fixed bit width selected, the binary, octal and hex columns show the two's complement representation; with width on Auto, the sign is kept (e.g. -2A in hex).
What is the maximum number size?
There is no practical limit. The converter uses JavaScript BigInt, so hundreds of digits convert exactly without losing precision.
Is my data sent anywhere?
No. All parsing and conversion happen locally in your browser. Nothing is uploaded, and the page works offline once loaded.