How large can the number be?

Arbitrarily large — conversion uses big integers, so there's no precision loss for huge values.

Are negative numbers or decimals supported?

This tool converts non-negative whole numbers. Fractions and signs aren't supported.

Why is my input invalid?

It contains a digit that doesn't exist in the selected base (for example, '2' in binary).

Is hex case-sensitive?

No. You can type hex digits in upper or lower case; output is shown in uppercase.

Number Base Converter

Convert

Enter a number in any base — binary, octal, decimal, or hexadecimal — and instantly see it in all four. Uses arbitrary-precision integers, so very large values convert exactly without rounding. Everything runs in your browser.

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Number

Input base

Binary

Octal

Decimal

Hexadecimal

How to use

Type a number into the input.
Select which base your number is written in.
Read the binary, octal, decimal, and hex results.
Copy any result with its Copy button.
Invalid digits for the chosen base show an error.

Frequently asked questions

How large can the number be?: Arbitrarily large — conversion uses big integers, so there's no precision loss for huge values.
Are negative numbers or decimals supported?: This tool converts non-negative whole numbers. Fractions and signs aren't supported.
Why is my input invalid?: It contains a digit that doesn't exist in the selected base (for example, '2' in binary).
Is hex case-sensitive?: No. You can type hex digits in upper or lower case; output is shown in uppercase.