Base32 Encoder / Decoder

Encode text into Base32 or decode Base32 back into text. Base32 uses only the 26 uppercase letters and the digits 2 through 7, which keeps it readable aloud and safe in places where case is not preserved, and it is the format two factor authentication secrets are shared in.

Text

Base32

How was this tool?

Your feedback helps us improve Base32 Encoder.

Why use Base32 Encoder?

Base32 solves a narrower problem than Base64. Both turn arbitrary data into printable characters, but Base32 optimises for a value a person might have to read, type, or say out loud rather than one a machine will copy. That priority explains the alphabet. Twenty six uppercase letters plus the digits 2 through 7 comes to exactly 32 symbols, which is five bits of information per character. Zero, one, and eight are deliberately absent because each is easy to mistake for a letter. The result is case insensitive and resistant to transcription errors, at the cost of output roughly 60 percent larger than the input. The most common place you will meet it is two factor authentication. When an app shows a setup key as text beneath the QR code, that key is Base32, precisely because someone may need to type it into a phone by hand without making a mistake.

Key benefits

Standard RFC 4648 alphabet, so output interoperates with other tools
Padding applied correctly to an eight character boundary
Decoding accepts lowercase and tolerates missing padding
Names the offending character when input is invalid, rather than failing generically
Runs in the page, which matters when the value is an authentication secret

Features

Encoding through a bit stream, grouping five bits per output character
Alphabet deliberately excludes 0, 1, and 8 to avoid confusion with O, I, and B
Equals sign padding to the standard block size
Error message identifying the exact invalid character on decode
Copy buttons on both directions

Popular use cases

Reading a two factor authentication secret shared as text instead of a QR code
Producing an identifier that survives being read over the phone
Encoding a value for a DNS label, where case is not preserved
Inspecting a Base32 string from a config file or a provisioning URI

How to use Base32 Encoder

1
Enter your text
Type or paste into the text field for encoding.
2
Encode it
The Base32 output uses uppercase letters A to Z and digits 2 to 7, padded with equals signs to a multiple of eight characters.
3
Decode in reverse
Paste Base32 into its own field and decode. Padding is optional on input and lowercase is accepted.
4
Copy what you need
Both fields have copy buttons.

Frequently asked questions

How is Base32 different from Base64?

Base32 uses a 32 character alphabet and encodes five bits per character, while Base64 uses 64 characters and encodes six. That makes Base32 output about 60 percent larger than the input against Base64s 33 percent, but the alphabet is case insensitive and avoids visually confusable characters, which is the tradeoff it exists to make.

Why does the alphabet skip 0, 1, and 8?

To remove ambiguity when a human reads or transcribes the value. Zero and capital O, one and capital I, and eight and capital B are all easy to confuse. Dropping the digits leaves only characters that are hard to mistake for one another.

Why are two factor secrets in Base32?

The authenticator setup key often has to be typed by hand when a QR code cannot be scanned. Base32 is case insensitive and free of confusable characters, which makes it far more reliable to transcribe than Base64 would be.

Are the equals signs required?

They pad the output to a multiple of eight characters, which some strict parsers expect. Decoding here strips them first, so a string with padding missing will still decode correctly.

Is my input uploaded anywhere?

No. Both directions run as plain JavaScript in the page. This matters especially for authentication secrets, which should never be pasted into a tool that sends them to a server.

Last reviewed: July 2026

How was this tool?

Related tools