Number Base Converter
Convert between binary, octal, decimal, and hexadecimal
Supports arbitrary-precision integers via BigInt. Underscores are stripped: 1_000_000 works.
How it works
- 1Type into any base
Enter a value in binary, octal, decimal, or hex — the others update instantly.
- 2Use underscores freely
1_000_000 or ff_ee_dd are stripped to the raw digits, matching Rust and modern JS syntax.
- 3Prefixes are optional
0b, 0o, and 0x prefixes are recognized but not required.
About Number Base Converter
Free online number base converter. Type a number in binary, octal, decimal, or hex — see all four representations update live. Handles arbitrary-precision integers via BigInt. Runs entirely in your browser. Number Base Converter on 712 Tools runs entirely inside your browser using modern JavaScript APIs — no server ever sees your data. That means instant results, complete privacy, and no upload limits.
Whether you need to convert between binary, octal, decimal, and hexadecimal for a debugging session, a quick sanity check, or a production incident, this tool is free to use as many times as you need. There are no watermarks, no sign-up, and no ads inside the tool itself.
Frequently asked questions
Is there a size limit?
No — BigInt supports arbitrary-precision integers. You can convert a 200-digit hex number just fine.
Does it support negative numbers?
Yes, in decimal. For negative hex/binary, encode with two's complement first — that's a different operation.
What about fractional numbers?
Not yet. This tool is for integers. Floats in binary/hex are a separate topic (IEEE 754).
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