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Number Base Converter

Convert between binary, octal, decimal and hexadecimal number systems.

Developer

Input

Use only characters valid in the base you chose; a “0x”, “0b” or “0o” prefix, if you type one, is ignored.

Calculated in your browser; what you enter is never sent to a server.

Result

Decimal

255

Binary
11111111
Octal
377
Hexadecimal
FF

How does it work?

Choose which base your number is already in and type it. The tool shows the same value in the other three bases (binary, octal, decimal, hexadecimal). Very large numbers — beyond JavaScript's safe integer limit — convert without losing precision.

Example

Which base?: Decimal (base 10) · Number: 255 → Decimal: 255

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Frequently asked questions

Can I convert negative numbers?

No, this tool only works with non-negative whole numbers (0 and above).

What if I type a prefix like 0x or 0b?

It's ignored; you can type the number with or without its usual prefix.

Can I convert decimals with a fractional part?

No, this tool only works with whole numbers.

Will a very large number lose precision?

No. The number is converted using integer arithmetic, not floating-point, so it comes out exact no matter how long it is.