Number Base Converter

Type a number in any format and see it in decimal, hex, binary, octal, and base36 at once. Prefix-aware: 0xFF is hex, 0b1010 is binary, 0o77 is octal. No prefix means decimal.

Common use cases

Reading file permissions. chmod 755 makes more sense when you see it's 111 101 101 in binary. Owner gets read+write+execute, group and others get read+execute.

Working with memory addresses and color codes. You're staring at 0x1A3F in a debugger and need the decimal value. Or converting a hex color to figure out its RGB breakdown.

Generating compact IDs. Base36 packs the most information into the fewest alphanumeric characters. That's why URL shorteners and video IDs use it. Type a big decimal, grab the base36 version.

Things to know

Uses BigInt internally, so there's no upper bound on number size. Your 256-bit key will convert fine. Number.MAX_SAFE_INTEGER doesn't apply here because we never touch a JavaScript Number.

Negative numbers work. The sign carries through to every base representation. -42 gives you -2A in hex, -101010 in binary.

Base36 uses digits 0-9 plus letters a-z. It's the densest standard alphanumeric encoding. Beyond that you're into Base58 or Base64, which use mixed case and special characters.

Privacy

All conversion happens in your browser. No server, no network request, no reason to worry about pasting internal values. We can't see what you type because there's nowhere for it to go.