util·tools

Number Base Converter

Convert a number between binary, octal, decimal and hexadecimal. Type into any one of the four fields and the others update instantly. It handles very large whole numbers and negatives, and runs entirely in your browser.

About this number base converter

Computers count in bases other than the everyday base 10. Binary (base 2) uses only 0 and 1 and is how machines store everything; hexadecimal (base 16) packs four binary digits into one and shows up in colour codes, memory addresses and byte values; octal (base 8) appears in file permissions. This number base converter ties all four together: type a value into any field — decimal, hex, binary or octal — and the other three update at once. It uses your browser's big-integer support, so it stays exact even for very large numbers that would lose precision in an ordinary calculator, and it handles a leading minus sign for negatives. Everything is worked out on your device, so nothing you enter is stored.

Frequently asked questions

How do I convert, say, decimal to hex?
Type your number into the Decimal field. The Hexadecimal, Binary and Octal fields fill in automatically — no button to press.
Can it handle very large numbers?
Yes. It uses big-integer maths, so even numbers far beyond a normal calculator's limit stay exact rather than being rounded.
Does it accept hex letters in any case?
Yes. Hexadecimal input accepts both upper and lower case (FF or ff), and results are shown in upper case by convention.

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