Base32 Decoder Online


About the Base32 Decode online tool,

Base 32 Decoder online tool for Decoding data in base32 to text or plaintext strings. It basically does is decode arbitrary binary data in ASCII text.

What is Base32?

Base32 is a transfer encoding is character set or encoding schemes that uses the 26 uppercase letters (A-Z) and the digits (2-7) and equal sign(=) as padding, as per the encoding scheme is defined in RFC 4648.

Here two digits 0 and 1 are not considered because of their similarity with the letters O and I. Which can be helpful when dealing with case-insensitive filesystems or any spoken language.

How does the base 32 encoder / base32 decoder works?

Base32 encoding schemes use the 26 uppercase letters A–Z, and the digits 2–7.

Here 0 and 1 are skipped due to their similarity with the letters O and I.


Let's Understand it with an Example:

Let's base32 encode the word "Cat",

Cat in ASCII decimal values =

[67, 97, 116]

Cat in binary format =

[01000011, 01100001, 01110100]

Steps to Encode String to Base32:

  1. Convert an input byte stream into a group of 5 bytes. If there are less than 5 bytes, at the end, add additional empty bytes.

    Group = [01000011, 01100001, 01110100, xxxxxxxx, xxxxxxxx]

  2. Divide this group into 8 chunks of 5 bits.

     Chunks = [01000, 01101, 10000, 10111, 0100x, xxxxx, xxxxx, xxxxx]

  3. If a chunk has both actual bits and empty bits, replace the remainings empty bits with all 0’s.

     Chunks = [01000, 01101, 10000, 10111, 01000, xxxxx, xxxxx, xxxxx]

  4. Convert each 5 bits chunk to its decimal value (0-31) (refer the table). If a 5 bits chunk contains empty bits replace with character ‘=’.

     Chunks = [8, 13, 16, 23, 8, =, =, =]


  5. BinaryDecimalBase32
    000000A
    000011B
    000102C
    000113D
    001004E
    001015F
    001106G
    001117H
    010008I
    010019J
    0101010K
    0101111L
    0110012M
    0110113N
    0111014O
    0111115P
    1000016Q
    1000117R
    1001018S
    1001119T
    1010020U
    1010121V
    1011022W
    1011123X
    1100024Y
    1100125Z
    11010262
    11011273
    11100284
    11101295
    11110306
    11111317

  6. In the base32 symbol chart, map each decimal value to its corresponding character.

      Chunks = [I, N, Q, X, I, =, =, =]

At finally, The word “Cat” base32 encoded value is "INQXI===".

Note that the Base32 Encoding process is just reverse of above proces.

How to identify a Base32 ciphertext?

A Base32 encoded message or data,

  • Is contains only of the characters 'ABCDEFGHIJKLMNOPQRSTUVWXYZ 234567 =' (no 0,1,8,9)
  • Alwayes string ends with 0,1,3,4 or 6 characters = (equal sign).
  • Generally it has a number of character multiples of 8.

Also Refer, Base32 Encode