Base32 Decoder — Base32 to Text Online
Decode Base32 text back to readable characters instantly — the standard RFC 4648 format used by TOTP/2FA secret keys. Free, client-side Base32 decoder.
🔒 100% Client-Side Processing
Your data is processed entirely in your browser and never transmitted to any server.
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Common Use Cases
Inspecting a 2FA secret key
Decode an authenticator app's Base32 secret to see its raw byte value while debugging a TOTP implementation.
Reversing legacy encoded identifiers
Recover the original text from Base32-encoded values found in older systems or protocols.
Frequently Asked Questions
- What characters are valid in Base32 input?
- Uppercase A-Z and digits 2-7 only (0, 1, 8, and 9 are deliberately excluded from the alphabet to avoid confusion with O, I, B, and G). Trailing = padding is stripped automatically; anything else is reported as invalid.
- I have a TOTP/2FA secret key — can I decode it here?
- Yes — authenticator app secret keys are Base32-encoded by convention. Paste the secret to see its raw bytes, though the app itself handles the actual time-based code generation.
- Can this also encode text into Base32?
- Yes — switch the toggle at the top and it encodes instead. Encoding grows your data by roughly 60 percent, since every five bytes become eight characters, which is why Base32 suits case-insensitive uses such as TOTP secrets and DNS labels rather than bulk payloads. Base32 Encoder starts in that direction.
- Is my data private when I use this tool?
- Yes. This tool runs entirely in your browser using client-side JavaScript — nothing you type is transmitted to, logged by, or stored on any server. You can safely process confidential text, tokens, or code.