Number Base Converter

Base 2 accepts only 0 and 1; base 8 accepts 0 to 7; base 10 accepts 0 to 9; base 16 adds A to F, upper or lower case. Custom bases from 2 to 36 extend the alphabet with letters up to Z, where Z equals 35. Anything outside the selected alphabet is reported as an error.

It parses your text in the selected base, then converts the value back to a string in that base and compares it with your input after normalizing case. Only an exact match counts, so stray characters, wrong digits or misplaced signs are caught immediately instead of being silently cut off, as can happen with naive parsing.

Hex maps neatly onto binary: each hexadecimal digit represents exactly four bits, so two digits describe one byte. Memory addresses, color codes, hashes and byte-level file formats are all written in hex because it stays compact while remaining directly readable against the underlying bits. Base 64 is different — it is an encoding, not a numeral system.

This tool handles negative integers: write a leading minus sign and the sign is carried through every result. Fractions and exponents are not supported, because numeral bases beyond decimal have no universal way to write a radix point — keep the input a plain integer for reliable, unambiguous conversions in every base.

Yes. Conversions use JavaScript number parsing and toString inside your browser, so nothing is uploaded and the results appear as you type. You can safely convert sensitive values such as internal IDs, color values or checksums without the data ever leaving your device.