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Base32 Encoder & Decoder

Convert text to Base32 and back using the standard RFC 4648 alphabet (A-Z, 2-7) with '=' padding. Everything runs in your browser.

How to use this tool

  1. 1

    Choose 'Encode' to turn text into Base32, or 'Decode' to turn Base32 back into text, using the mode dropdown.

  2. 2

    Type or paste your input into the text box — UTF-8 text when encoding, or a Base32 string when decoding.

  3. 3

    Read the result in the gray output panel below; it updates instantly as you type, with no button to press.

  4. 4

    Select and copy the output text to use it elsewhere.

What is Base32 encoding?

Base32 is a binary-to-text encoding defined in RFC 4648 that represents data using 32 printable characters: the uppercase letters A-Z and the digits 2-7. It works by reading the input as a stream of bits and slicing it into 5-bit groups (2^5 = 32), mapping each group to one alphabet character. Because the input is grouped in 40-bit blocks (the least common multiple of 5 and 8), the output is padded with '=' characters until its length is a multiple of 8. This tool encodes the UTF-8 bytes of whatever text you type, so multi-byte characters like emoji or accented letters expand into several bytes before encoding. The trade-off versus Base64 is size: Base32 needs 8 characters per 5 bytes (about 60% overhead) rather than 4 characters per 3 bytes. In return it omits the easily-confused characters 0, 1, 8, and 9 and is case-insensitive, which makes it well suited to values people read aloud, type by hand, or embed in case-folding systems like DNS. Note this tool uses the standard alphabet, not the base32hex or Crockford variants, which order their characters differently and will not interoperate.

Common use cases

  • Inspecting a TOTP/2FA setup string by decoding the Base32 secret an authenticator app expects.

  • Encoding a short identifier into a case-insensitive form safe to drop into a DNS label or subdomain.

  • Hand-checking the output of a server library against a known-good Base32 implementation while debugging.

  • Producing tokens or codes meant to be read aloud or typed without confusing 0/O or 1/I/l.

  • Decoding a Base32 string copied from a config file or QR-code payload to see the underlying text.

  • Teaching or learning how bit-level encodings group data, by watching how input maps to 5-bit chunks.

Frequently asked questions

Why use Base32 instead of Base64?▼
Base32 is less compact — 8 characters per 5 bytes versus Base64's 4 characters per 3 bytes — but it is case-insensitive and drops visually ambiguous characters like 0, 1, 8 and 9. That makes it easier for people to transcribe by hand or read aloud, and safe for case-insensitive systems such as DNS.
Which Base32 variant does this tool use?▼
It uses the standard RFC 4648 alphabet: A-Z followed by 2-7, with '=' as the padding character. It does not implement the base32hex or Crockford Base32 variants, which use different character orderings and are not compatible.
Can I encode files or raw binary data?▼
No. This tool works on text only. When encoding it converts your text to UTF-8 bytes first; when decoding it interprets the resulting bytes back as UTF-8 text. It does not accept file uploads or hex input.
Why does decoding sometimes produce odd or replacement characters?▼
Decoding is lenient: it uppercases input, strips '=' padding, and skips any character not in the A-Z2-7 alphabet (including spaces and line breaks). If the bytes it recovers are not valid UTF-8 — for example because the original data was raw binary, not text — the browser's decoder may show replacement characters.
Can I decode a TOTP secret to see the raw key?▼
Only partially. Authenticator secrets are random binary keys shown in Base32. This tool will decode the Base32, but it then renders the bytes as UTF-8 text, so a binary key will usually appear as garbled or replacement characters rather than a clean value. It is useful for checking the Base32 itself, not for extracting the raw key bytes.
Is my data sent to a server?▼
No. All encoding and decoding happens locally in your browser using JavaScript. Nothing you type is uploaded, logged, or stored.

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