Base32 Encoder/Decoder - TOTP Secret Key Converter Online

Encode and decode Base32 for TOTP 2FA secrets, DNS records, and Tor addresses. RFC 4648 compliant. Free online Base32 converter.

Raw Data

0 bytes

Base32

0 chars

Include padding (=)

Uppercase output

Common Use Cases

TOTP/2FA

Secret keys for Google Authenticator, Authy, and other 2FA apps use Base32. Decode to get raw HMAC key bytes.

Tor Onion v3

.onion addresses are Base32-encoded public keys. 56 characters encode the 32-byte ed25519 key + checksum.

DNSSEC NSEC3

NSEC3 records use Base32hex for hashed domain names, preserving sort order for efficient lookups.

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Frequently Asked Questions

Base32 encodes binary data using 32 characters (A-Z and 2-7). It's less efficient than Base64 but uses only uppercase letters and numbers, avoiding confusion between similar characters.

Base32 is used in TOTP/HOTP 2FA secret keys (Google Authenticator), Tor .onion addresses, DNSSEC NSEC3, file systems with case-insensitive names, and some barcode formats.

TOTP (Time-based One-Time Password) uses Base32 for secret keys because it's easy to type manually and avoids ambiguous characters (0/O, 1/I/l). Apps like Google Authenticator use Base32 secrets.

Base64 uses 64 characters (A-Z, a-z, 0-9, +, /) with 33% overhead. Base32 uses 32 characters (A-Z, 2-7) with 60% overhead. Base32 is case-insensitive and more human-friendly.

Base32hex uses 0-9 and A-V instead of A-Z and 2-7. It preserves sort order of the original data, useful for databases and NSEC3 DNS records.

To avoid confusion: 0 looks like O, 1 looks like I or l, 8 looks like B, 9 looks like g. Using only 2-7 eliminates these ambiguous characters.

The TOTP secret key (usually 16-32 Base32 characters) is shared between server and app. Decode Base32 to get the raw bytes used in HMAC-SHA1 for code generation.

Yes. All encoding happens in your browser using JavaScript. Your data and secrets never leave your device.

TOTP/2FA

Tor Onion v3

DNSSEC NSEC3

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