HTMLNumber Base Converter
Convert numbers between decimal, hexadecimal, binary, and octal. Enter any value in any base and all others update instantly. Handles large integers and shows the calculation.
Ctrl+Enter to run | Ctrl+K to switch tools | Recent button shows input history
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What is the maximum number supported?
JavaScript safe integers up to 2^53-1. For larger numbers, use a dedicated big-integer library.
Can I enter hex with 0x prefix?
Yes — the hex field accepts values with or without the 0x prefix.