Base64 to Hex Converter (and back)

Text encoders convert characters to Base64 or hex. This converts directly between the two byte representations — Base64 in, hex out, or hex in, Base64 out — without assuming the bytes are text.

Any. Spaces, colons, newlines and 0x or \x prefixes are stripped, then the remaining hex digits are read two at a time. An odd number of digits is reported as an error.

It uses - and _ instead of + and / and omits = padding (RFC 4648 §5). Enable it to decode such input or to produce URL-safe output.

No. The conversion happens entirely in your browser; nothing is uploaded.

No, it is how Base64 works. The final character of an unpadded group carries spare low bits that decode to nothing, and the browser's decoder ignores them rather than rejecting the input, so QQ== and QR== both produce the single byte 41. Converting back always emits the canonical form (QQ==), which is why a Base64 → hex → Base64 round trip can hand you a different string than you started with. The bytes are identical; only the non-canonical spelling is lost.

Base64, by a wide margin. Hex is exactly two characters per byte — 100% overhead — while Base64 is four characters per three bytes, about 33%. A 32-byte key is 64 hex characters, 44 standard Base64 characters, or 43 in URL-safe form once the padding is dropped. Hex wins on readability instead: you can point at byte 7 by counting, and a single-character typo is always caught, whereas in Base64 one wrong character silently shifts three bytes.