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Number Base Converter
Type a number in any box, binary, octal, decimal, hexadecimal or a base of your choice, and the others update as you type. Numbers of any length are converted exactly.
Loading Number Base Converter…
Runs on your device. Nothing you paste is uploaded.
How to use the Number Base Converter
- Type or paste a number into the box for its base. Prefixes like 0x, 0b and 0o are understood.
- Read the same value in every other base. Binary is grouped in fours so it’s easier to read.
- For negative numbers, pick a bit width to see the two’s complement form used by computers.
Private by design
Plenty of online tools send what you paste to their server, which is a real risk with API keys, tokens and customer data. Number Base Converter runs entirely in your browser: nothing is uploaded, logged or stored, and it keeps working with your network switched off. It’s free, with no account and no limits.
Questions
How do I convert binary to decimal by hand?
Multiply each digit by 2 raised to its position, counting from 0 on the right, and add them up. 1011 is 1×8 + 0×4 + 1×2 + 1×1 = 11.
How big a number can it convert?
Any size. Numbers are held as JavaScript BigInts, so a 256-bit hash or a 100-digit decimal converts without rounding.
What is two’s complement?
How computers store negative whole numbers: invert every bit of the positive value and add 1. In 8 bits, −5 is 11111011 (0xFB). Choose a width of 8, 16, 32 or 64 bits to see it.
Is anything I paste sent to a server?
No. Every tool runs in your browser, so tokens, keys, customer data and code stay on your device. Once the page has loaded, the tools work offline too.
Do I need an account?
No. Every developer tool is free to use without signing in, with no limits.
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