Base Converter
Binary, hex, decimal, octal.
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About Base Converter
Enter a number, pick the base it's written in (binary, octal, decimal, or hexadecimal), and this converter instantly shows the value in all four bases. Each result has its own Copy button, uppercase hex, and a clear error if you type a digit that isn't valid for the chosen base.
It's completely free with no sign-up, no ads, and no limits. Every conversion runs entirely in your browser using exact big-number math, so nothing you type is ever uploaded to a server.
Frequently asked questions
- Is the number base converter free to use?
- Yes. It's 100% free with no account, no sign-up, and no usage limits. Convert as many numbers as you like.
- Is my data uploaded or stored anywhere?
- No. All conversion happens locally in your browser using JavaScript. The numbers you type never leave your device and are not sent to any server.
- Which number bases does it support?
- It converts between binary (base 2), octal (base 8), decimal (base 10), and hexadecimal (base 16). Choose the base your input is written in and it shows the value in all four at once.
- What happens if I enter an invalid digit?
- The tool validates your input against the selected base and shows a clear error listing exactly which characters aren't allowed — for example, the digit 2 or the letter G is not valid in binary.
- Can it handle very large numbers?
- Yes. It uses arbitrary-precision big-integer math, so large values convert exactly without rounding errors or overflow that ordinary calculators would produce.
- Is hexadecimal shown in uppercase, and can I copy the results?
- Hex output is shown in uppercase (A-F). Every result row — binary, octal, decimal, and hex — has its own Copy button that copies the value to your clipboard with a quick confirmation.