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Hazuu Tools

Base32 Decode

Decode Base32 strings to plain text — paste, decode, and copy instantly.

Input Base32
Output Text
Decoded text will appear here...
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About Base32 Decode

Base32 Decode is a free online tool that converts Base32-encoded strings back into their original plain text. Base32 encodes binary data using only 32 characters — the uppercase letters A through Z and the digits 2 through 7 — making it safe for case-insensitive environments such as DNS labels, file systems that ignore case, and two-factor authentication secret keys. When you receive one of these strings and need to read its raw content, this tool reverses the encoding instantly.

The decoder is built for practical situations: inspecting a TOTP/HOTP secret before entering it into an authenticator app, verifying a Base32-encoded configuration value, checking a Tor v3 onion address component, or auditing a token passed through a system that cannot handle arbitrary bytes. Unlike Base64, Base32 avoids characters such as + / = that can break URL parsing and shell variables, so it turns up in places where Base64 would cause problems.

All decoding runs entirely in your browser using JavaScript. The Base32 string you paste is never sent to a server, stored in any log, or shared with a third party. The tool accepts both padded (trailing =) and unpadded input, normalises lowercase to uppercase automatically, and uses the TextDecoder API to reconstruct multi-byte UTF-8 characters faithfully. There are no file size limits, no accounts, and no cost.

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Key Features

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RFC 4648 Base32 alphabet

Decodes the standard A-Z / 2-7 alphabet defined in RFC 4648. Padding characters (=) are stripped automatically, so both padded and unpadded input decode correctly.

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Case-insensitive input

Accepts uppercase, lowercase, or mixed-case input. The decoder normalises to uppercase before processing, matching the real-world habit of copying TOTP secrets in lowercase.

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Full UTF-8 output

Reconstructed bytes are decoded via the native TextDecoder API, so text originally encoded in any language or character set is reproduced correctly, not as garbled bytes.

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Instant error feedback

If the input contains a character outside the Base32 alphabet, the tool immediately identifies the offending character rather than silently producing corrupt output.

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100% client-side privacy

The JavaScript decode function runs entirely in your browser. TOTP secrets, API tokens, and other sensitive values never leave your machine.

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One-click copy

Copy the decoded result to the clipboard with a single click, ready to paste into a terminal, config file, or authenticator app.

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How to Use

01

Paste Base32

Paste your Base32-encoded string into the input pane.

02

Decode

Click "Decode" to convert the Base32 string back to readable text.

03

Copy Result

Use the copy button to grab your decoded text.

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Example

A Base32-encoded string is converted back to its original plain text. Trailing padding characters and lowercase input are handled automatically.

Base32 input
ONSWG4TFOQYTEMY=
Decoded text
secret123
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Common Use Cases

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    Inspecting TOTP/HOTP authenticator secrets

    Two-factor authentication apps store secrets as Base32 strings. Decode the secret before entering it manually to confirm the value is correct and matches what your server expects.

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    Verifying Base32-encoded configuration values

    Some config systems, CI pipelines, and secrets managers pass tokens through Base32 to avoid special-character escaping issues. Decode the value directly here without needing a local script.

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    Auditing tokens in case-insensitive systems

    DNS labels, certain file systems, and legacy email systems all fold case. Base32 was designed for these environments. Decode Base32 tokens from those systems to read their underlying content.

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    Checking Tor v3 onion address components

    Tor v3 .onion addresses embed Base32-encoded data. This tool lets you inspect that encoded segment to understand what it contains without installing specialist software.

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    Debugging encoded data in logs and URLs

    When a Base32 string appears in a server log, a query parameter, or an API response, paste it here to read the underlying value and quickly determine what it represents.

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Frequently Asked Questions

What is Base32 Decode? expand_more
Base32 Decode is a free online tool that converts Base32-encoded strings back into their original plain text form. It reverses the Base32 encoding process, transforming the 32-character representation (A-Z, 2-7) back into readable text.
What is Base32 used for? expand_more
Base32 is commonly used for TOTP/HOTP secret keys in two-factor authentication apps like Google Authenticator, DNS record encoding, Tor v3 onion addresses, and any system that requires case-insensitive encoding where Base64 special characters would be problematic.
Is my data secure? expand_more
Yes. All decoding happens entirely in your browser using JavaScript. No data is sent to any server, ensuring your encoded data remains completely private and secure.
What if my Base32 string is invalid? expand_more
If the input contains characters outside the Base32 alphabet (A-Z, 2-7, =), the tool will display a clear error message identifying the invalid character.
Does it matter if the input is uppercase or lowercase? expand_more
No. The decoder automatically normalises lowercase letters to uppercase before processing, so you can paste Base32 strings in any case without getting an error.
Does it require padding characters (=)? expand_more
No. Trailing = padding characters are stripped before decoding, so both padded and unpadded Base32 strings are accepted and produce the same result.
How is Base32 Decode different from Base32 Encode? expand_more
Base32 Encode converts plain text into a Base32 string; Base32 Decode does the reverse, converting a Base32 string back into plain text. Use the encode tool when you need to produce a Base32 representation, and this decode tool when you need to read what a Base32 string contains.
How is Base32 Decode different from Base64 Decode? expand_more
Both decode binary-to-text encodings, but Base32 uses only 32 characters (A-Z and 2-7) while Base64 uses 64 characters including + / and =. Base32 is chosen when output must be case-insensitive or when special characters would break the surrounding system. If you have a string that contains + / or mixed alphanumeric characters outside the 2-7 range, it is Base64, not Base32.