Convert numbers between binary, octal, decimal, hex, and any base 2–36.
Convert a number between any bases from 2 to 36 — binary, octal, decimal, hexadecimal, and custom bases — showing all of them at once. Uses BigInt for full precision on very large numbers. Runs entirely in your browser.
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Because it maps cleanly onto binary — each hex digit is exactly four bits, so a byte is always two hex digits. That makes memory addresses, colour codes and byte values compact and readable in a way decimal never manages, since decimal does not align with binary boundaries at all.
Yes, conversion uses arbitrary-precision arithmetic rather than standard floating point. That matters because JavaScript numbers lose precision above 2^53 — large IDs, hashes and 64-bit values silently become wrong in many online converters. Here they convert exactly.
Base 36 uses digits plus the full alphabet, which produces the shortest human-typable representation of a number — handy for short URLs and compact IDs. Base 32 appears in encoding schemes that avoid ambiguous characters, and base 8 survives mainly in Unix file permissions.
Yes, Number Base Converter is completely free. No signup, no account, and no watermark on outputs. A Pro tier is available for 100 AI ops/day and larger file sizes.
Number Base Converter runs entirely in your browser. Your file is never uploaded — it is read, processed and saved locally, so it never reaches our servers or anyone else's. You can disconnect from the internet after the page loads and it still works.
Input base
What it does: Converts a number between any bases from 2 to 36 — including the common binary, octal, decimal, and hexadecimal — showing all of them at once.
Full precision: Conversions use BigInt, so even numbers far larger than JavaScript’s safe integer limit convert exactly, with no rounding errors.
Uses: Reading hex color values and memory addresses, working with bit masks and permissions, decoding binary, and any low-level or embedded work.
Privacy: Everything runs locally in your browser. Nothing is sent to a server, so it works offline.