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Number Base Converter

Type a value in any base from 2 to 36 and read it back as binary, octal, decimal, hexadecimal, or a custom base — all at once.

Quick presets

Value

From base

Base:

Bits –

Tap a bit to flip it.

Any base

Result

Signed integer views (two's complement)

Runs in your browser — nothing you enter is uploaded or stored.

ToolFeather · Base 2–36

Scratchpad auto-saved

Stored in this browser (localStorage)

About the Number Base Converter

Every number can be written in different bases (also called radixes). Base 10 is the everyday decimal system, base 2 is binary, base 16 is hexadecimal, and so on up to base 36, where the digits run 0–9 then A–Z. This converter reads your value in whatever base you specify and re-expresses the same quantity in several others.

Enter the number, set the source base to match how you typed it, and the tool instantly shows the binary, octal, decimal and hexadecimal forms. The custom target base field lets you pick any other base from 2 to 36 for a one-off conversion. If a digit is illegal for the chosen base — for example the letter G in base 16, or the digit 2 in binary — you get a clear error instead of a wrong answer.

Conversions use arbitrary-precision integer maths, so very long values stay exact rather than rounding once they exceed normal number limits. Everything is computed on your device, which makes it safe for license keys, hashes or any value you would rather not send to a server.

Examples

Enter 1010 with source base 2 → decimal 10, hex A.

Enter FF with source base 16 → decimal 255, binary 11111111.

Enter 255 in base 10, set custom target base to 36 → 73.

Type 102 in base 2 → error, because 2 is not a valid binary digit.

Frequently asked questions

5 answers

Which bases are supported?

Any whole-number base from 2 to 36. Above 10, letters A–Z stand in for digit values 10 to 35, so base 36 uses 0–9 then A–Z.

Is the conversion case-sensitive?

No. Letter digits and the hexadecimal output are handled case-insensitively, so ff and FF are treated the same on input.

Can it handle very large numbers?

Yes. It uses arbitrary-precision integers, so long binary strings or big hex values convert exactly without losing precision.

Does it convert fractions or decimals?

This tool works on whole numbers. Fractional base conversion follows different rules and is not covered here.

Is my input sent anywhere?

No. All parsing and conversion happen locally in your browser, so nothing you type is uploaded.