Turn reviewed UTF-8 text or hexadecimal byte pairs into uppercase RFC 4648 Base16.
Limited to 512 KiB of bytes and 1 MiB of encoded text.
Decoder reports keep lowercase hexadecimal authoritative.
Explicit byte-to-text semantics
Base16 writes every byte as two hexadecimal characters. UTF-8 and hexadecimal source modes stay separate so text encoding never masquerades as raw-byte parsing.
Base16 writes every byte as two hexadecimal characters. UTF-8 and hexadecimal source modes stay separate so text encoding never masquerades as raw-byte parsing.
The result uses uppercase A-F and requires no padding. The byte count records the exact source length before the two-to-one expansion.
Encoder text is converted with UTF-8 only after malformed surrogate pairs are rejected. Hex mode accepts exact byte pairs without 0x, spaces, or separators. Decoder hex is authoritative; a text preview appears only when the bytes are valid UTF-8.
The work starts only when you submit the form. Source text, byte values, and results stay in the current browser tab; Tool Swim does not upload them, log their content, save presets, or call a developer API.
Base16, Base32, Base64, and Base85 allow at most 512 KiB of source or decoded bytes and 1 MiB of encoded text. Bitcoin Base58 is limited to 4,096 bytes or 5,600 characters because generic radix conversion is quadratic.
