Base32 Encoder / Decoder

Encode and decode Base32 online

This Base32 encoder and decoder converts text to standard RFC 4648 Base32 and decodes Base32 strings back into readable text. It uses the alphabet A–Z and 2–7 and pads output with =.

How to use it

1. Choose Encode → Base32 or Decode ← Base32.
2. Type or paste your input. The output updates as you type.
3. Click Copy output, or Use as input to swap the output into the input box and switch mode.

Below the boxes you can see the input length, output length and the expansion ratio.

How Base32 works

Text is first turned into UTF-8 bytes. The bytes are joined into one long string of bits, which is cut into groups of 5 bits. Each group (a value from 0 to 31) maps to one character of the alphabet. Every 5 bytes become 8 characters, and the output is padded with = to a multiple of 8.

Example: Hello is 5 bytes, so it encodes to exactly 8 characters: JBSWY3DP. Hi is 2 bytes and encodes to JBUQ====. Hello, World! (13 bytes) becomes JBSWY3DPFQQFO33SNRSCC===.

Decoding rules

• Spaces and line breaks are removed before decoding.
• Lowercase letters are accepted and treated as uppercase.
• Trailing = padding is optional.
• Any other character, such as 0, 1, 8 or 9, shows an error with the character and its position.
• Decoded bytes are shown as UTF-8 text. Binary data that is not valid text will show replacement characters.

Common uses

• Secret keys for TOTP and HOTP two-factor authentication apps.
• Identifiers that must survive case changes or be read aloud.
• Systems that cannot handle the + and / characters used by Base64.

Frequently asked questions

Is Base32 encryption?

No. Base32 is an encoding, not encryption. Anyone can decode it, so do not use it to protect secrets.

Why is Base32 longer than Base64?

Each Base32 character carries 5 bits instead of 6, so the output is about 60% larger than the input, compared with about 33% for Base64.

Is my data sent to a server?

No. Encoding and decoding run entirely in your browser.