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base32-encoder

Base32 is a binary-to-text encoding that uses 32 characters (A-Z and 2-7) to represent 5 bytes per 8 characters of output. The ZTools Base32 Encoder & Decoder follows RFC 4648, supporting standard Base32 (A-Z, 2-7) and Base32hex (0-9, A-V) variants. Base32 is used in TOTP authenticator apps (the QR codes contain a Base32-encoded secret), S3 access keys, DNS responses, and case-insensitive identifiers because its alphabet excludes ambiguous characters (no 0/O, no 1/I) and is case-insensitive.

Use cases​

Decoding a TOTP secret from an authenticator QR code​

Two-factor authentication apps store the shared secret as a Base32 string. When migrating between apps or backing up secrets, decode the Base32 here, save the raw bytes, and re-encode when registering with a new device.

Generating case-insensitive identifiers for shared URLs​

Base32 strings can be spoken aloud and typed without case sensitivity issues — useful for short URL codes, redemption codes, or anything users have to read or type.

Encoding binary data for DNS TXT records​

DNS TXT record content has limited charset support. Base32 fits cleanly without escaping, unlike Base64 which uses +, /, =. Useful for email auth (DKIM) or telemetry payloads.

Working with Z-Base-32 or Crockford's Base32 (with mode switching)​

Different Base32 variants exist (Z-Base-32 for human-friendly encoding, Crockford's for short identifiers). The tool supports the standard variants and translates between them when needed.

How it works​

  1. Paste text or hex into the input pane — For encoding: raw text or hex bytes (0xDEADBEEF). For decoding: Base32 string (case-insensitive, padding optional).
  2. Choose the variant — Standard Base32 (RFC 4648, A-Z + 2-7), Base32hex (RFC 4648, 0-9 + A-V), or Crockford's Base32.
  3. Click Convert — Encoding: each 5-byte block becomes 8 Base32 chars (with = padding for partial blocks). Decoding: 8 chars become 5 bytes (padding stripped automatically).
  4. Review the output — Output shown with byte count and character count. Decoded binary is shown as hex + UTF-8 attempt for readability.
  5. Copy or download — One-click copy or save decoded binary as .bin.

Examples​

Input: Encode: "Hello"

Output: JBSWY3DPEB3W64TMMQ======

Input: Decode: JBSWY3DPEB3W64TMMQ======

Output: Hello

Frequently asked questions​

How does Base32 differ from Base64?

Base64 uses 64 characters (A-Z, a-z, 0-9, +, /) and encodes 3 bytes per 4 characters. Base32 uses 32 characters (A-Z, 2-7) and encodes 5 bytes per 8 characters. Base32 is ~20% larger but case-insensitive and avoids URL/filename-unsafe chars.

Why does Base32 skip 0, 1, 8, 9?

To avoid ambiguity — 0 looks like O, 1 looks like I and l, 8 and 9 aren't needed in the 32-char alphabet. The omission makes Base32 strings safer to dictate or transcribe by hand.

Is the padding (=) required?

RFC 4648 requires it for unambiguous decoding of streams. For self-contained strings, padding is often optional and decoders accept both. The tool emits padding by default but accepts unpadded input.

What is Base32hex?

A variant using 0-9 + A-V (instead of A-Z + 2-7). Order is preserved with binary, so sorted Base32hex strings sort the same as their decoded bytes — useful for sortable identifiers.

Why do TOTP secrets use Base32?

TOTP authenticator apps need users to type the secret on tiny phone keyboards in some setup flows. Base32's case-insensitive, ambiguity-free alphabet is the safest choice for human transcription.

Is the encoding offline?

Yes. The tool runs entirely in your browser and never uploads input.

Tips​

  • For TOTP, always use standard Base32 — that's what RFC 6238 specifies.
  • For sortable identifiers, prefer Base32hex (sorts the same as the decoded bytes).
  • For human-friendly short codes, Crockford's Base32 (23456789ABCDEFGHJKMNPQRSTVWXYZ) is even safer to dictate.
  • Padding is optional in many decoders but always emit it for max compatibility.

Try it now​

The full base32-encoder runs in your browser at https://ztools.zaions.com/base32-encoder — no signup, no upload, no data leaves your device.

Open the tool ↗

Last updated: 2026-05-05 · Author: Ahsan Mahmood · Edit this page on GitHub