Number Base Converter
Convert numbers between binary, octal, decimal, hexadecimal, and any base from 2 to 36. Type in any field and the rest update live. Everything runs in your browser.
BigInt math, so it handles very large numbers exactly. Nothing is uploaded or logged.About the Number Base Converter
The Number Base Converter changes a number between binary, octal, decimal, hexadecimal, and any base from 2 to 36. Type a value in any field and every other field updates at once, so you can read the same number in several systems side by side. It is built for developers, students, and anyone working with bitmasks, color codes, file permissions, or low-level data. Conversion uses native BigInt math in your browser, so it handles very large numbers exactly and your input is never uploaded.
How it works
- Type or paste a number into any field: binary, octal, decimal, hexadecimal, or the custom base.
- The other fields update live with the same value in their base; invalid characters are flagged inline with the digits that are allowed.
- Set the custom base to any value from 2 to 36 to convert into bases like 3, 12, or 36.
- Read the bit length, byte length, and decimal value below the fields, or click Clear to start over.
Features
- Live conversion across binary, octal, decimal, and hexadecimal in one view.
- Custom base input for any base from 2 to 36.
- Per-base character validation with a clear inline error and the list of allowed digits.
- BigInt math for exact conversion of very large numbers, with negative value support.
- Bit length, byte length, and decimal readout for the current number.
Frequently asked questions
Is my data uploaded anywhere?
No. All conversion runs in your browser using native BigInt math. Nothing is sent to a server or logged.
What bases are supported?
Binary, octal, decimal, and hexadecimal have dedicated fields. The custom base field accepts any base from 2 to 36, using digits 0 to 9 and letters A to Z.
Can it handle very large numbers?
Yes. The tool uses BigInt, so it converts integers far beyond the normal 64-bit range without losing precision.
Why does a field show an error?
Each base allows only certain digits. For example, binary allows only 0 and 1, and hexadecimal allows 0 to 9 and A to F. If you enter a character outside the base, the field is marked and the allowed digits are shown.
Does it work with negative numbers and decimals?
It converts negative integers, shown with a leading minus sign. Fractional values are not supported; the tool works with whole numbers.