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Base32 Converter

Encode text to Base32 and decode Base32 strings back to text

Conversion Mode

Text Input

Base32 Output

Output will appear here

Base32 Alphabet

A

0

B

1

C

2

D

3

E

4

F

5

G

6

H

7

I

8

J

9

K

10

L

11

M

12

N

13

O

14

P

15

Q

16

R

17

S

18

T

19

U

20

V

21

W

22

X

23

Y

24

Z

25

2

26

3

27

4

28

5

29

6

30

7

31

About Base32

Base32 encoding converts binary data into a text format using 32 ASCII characters (A-Z and 2-7).

Each character represents 5 bits of data, making it less efficient than Base64 but more human-readable.

Base32 is commonly used in TOTP (Time-based One-Time Password) systems and file naming.

What Is Base32 Encoding?

Base32 encoding is a binary-to-text encoding scheme that represents arbitrary binary data using a alphabet of 32 printable ASCII characters. The standard Base32 alphabet uses uppercase letters A through Z and the digits 2 through 7, chosen for their clarity and resistance to misreadings. Each Base32 character encodes exactly 5 bits of data, making the encoding less space-efficient than Base64 (which uses 6 bits per character) but more readable and resistant to transcription errors.

Base32 was designed to solve a specific problem: encoding binary data in contexts that only reliably support uppercase letters and digits. Many legacy systems, file systems, and communication protocols were originally designed for alphanumeric text and could not safely handle characters like +, /, or = that appear in Base64. Base32 avoids these problematic characters entirely, using only the unambiguous subset of the ASCII character set.

The most prominent use of Base32 is in TOTP (Time-based One-Time Password) systems like Google Authenticator and Authy. When you scan a QR code to set up two-factor authentication, the secret key is typically encoded as a Base32 string. Base32 is also used in DNS for encoding certain data records, in file naming schemes where special characters must be avoided, and in various protocols that require alphanumeric-only encoding.

How Base32 Encoding Works

Base32 encoding converts binary data to text through a series of bit-grouping steps. The process groups input bits into 5-bit chunks and maps each chunk to a character in the Base32 alphabet.

Base32 Encoding Process

Each 5-bit group → Base32 alphabet character

Where:

  • Input= Original binary data (8-bit bytes)
  • 5-bit chunks= Input bits regrouped into sets of 5
  • Output= Base32 encoded string (= and padding added as needed)

The Base32 Alphabet

The Base32 alphabet consists of 32 characters, each representing a value from 0 to 31. The alphabet is carefully chosen to exclude visually ambiguous characters and those that might be problematic in various encoding contexts.

Value Character Value Character
0-7A-H16-23Q-X
8-15I-P24-31Y-Z, 2-7

The characters 0, 1, 8, and 9 are deliberately excluded because they are frequently confused with O, l, B, and g respectively. The equals sign (=) is used as padding when the encoded data is not a multiple of 5 bytes, similar to how Base64 uses padding.

How to Use This Calculator

The Base32 converter supports both encoding (text to Base32) and decoding (Base32 to text):

  1. Choose the conversion mode: Click "Text → Base32" to encode text, or "Base32 → Text" to decode a Base32 string.
  2. Enter the input: Type or paste your text (for encoding) or Base32 string (for decoding) into the input area.
  3. View the result: The converted output appears instantly in the result panel. Invalid input is flagged with an error message.

The Base32 alphabet reference chart is displayed below the converter, showing the mapping between each character and its numeric value.

Real-World Applications

Base32 is most widely known for its role in two-factor authentication (2FA). When you scan a QR code to set up Google Authenticator, Microsoft Authenticator, or similar apps, the shared secret is encoded as a Base32 string. This encoding ensures the secret can be reliably transmitted through QR codes and manual entry without ambiguity.

In DNS and networking, Base32 encoding is used in various record types and protocols. The DNSSEC specification uses Base32 to encode certain data fields, and some proprietary APIs use Base32 for encoding binary tokens in URLs or headers.

File naming and storage applications sometimes use Base32 when file names must contain only alphanumeric characters. For example, some email systems encode binary content identifiers using Base32 to ensure they remain valid across different file systems and operating systems that may have restrictions on special characters in file names.

Worked Examples

Encoding Text to Base32

Problem:

Encode the word 'Hello' to Base32.

Solution Steps:

  1. 1Convert each character to its ASCII binary: H=01001000, e=01100101, l=01101100, l=01101100, o=01101111
  2. 2Concatenate all bits: 0100100001100101011011000110110001101111
  3. 3Group into 5-bit chunks: 01001 00001 10010 10110 11000 11011 00011 01111
  4. 4Map each chunk to the Base32 alphabet: JBSW Y3DP E3I6
  5. 5Add padding to make output a multiple of 8 characters: JBSWY3DP

Result:

'Hello' encoded in Base32 = JBSWY3DP

Decoding Base32 to Text

Problem:

Decode the Base32 string 'JBSWY3DP' back to text.

Solution Steps:

  1. 1Remove any padding characters (=): JBSWY3DP
  2. 2Map each character to its 5-bit value: J=9, B=1, S=18, W=22, Y=24, 3=27, D=3, P=15
  3. 3Convert to binary: 01001 00001 10010 10110 11000 11011 00011 01111
  4. 4Regroup into 8-bit bytes: 01001000 01100101 01101100 01101100 01101111
  5. 5Convert bytes to ASCII: H, e, l, l, o

Result:

JBSWY3DP decoded = 'Hello'

Comparing Base32 and Base64 Efficiency

Problem:

How many characters does it take to encode the 16-byte string 'abcdefghijklmnop' in Base32 versus Base64?

Solution Steps:

  1. 116 bytes = 128 bits
  2. 2Base32: 128 bits / 5 bits per character = 25.6, rounded up to 32 characters (with padding)
  3. 3Base64: 128 bits / 6 bits per character = 21.33, rounded up to 24 characters
  4. 4Base32 produces 32 characters vs Base64's 24, confirming Base64 is more space-efficient

Result:

Base32 uses 32 characters, Base64 uses 24 characters for the same data — Base64 is 33% more efficient

Tips & Best Practices

  • ✓Base32 is ideal for encoding 2FA secrets — it's the standard format used by authenticator apps
  • ✓Output length is always a multiple of 8 characters (padded with = if needed)
  • ✓Base32 strings are case-insensitive — 'JBSWY3DP' and 'jbswy3dp' decode to the same value
  • ✓The excluded characters (0, 1, 8, 9) prevent confusion between similar-looking glyphs
  • ✓Base32 is less efficient than Base64 but safer for human transcription and QR codes
  • ✓Use Base32 when you need alphanumeric-only encoding without special characters

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Frequently Asked Questions

Base32 uses 32 characters (A-Z and 2-7) with 5 bits per character, while Base64 uses 64 characters (A-Z, a-z, 0-9, +, /) with 6 bits per character. Base64 is more space-efficient (about 33% shorter output) but Base32 is more suitable for contexts that only support uppercase letters and digits, such as QR codes for 2FA secrets.
Base32 excludes 0, 1, 8, and 9 because these digits are frequently confused with similar-looking letters: 0 with O, 1 with I or l, 8 with B. By removing these ambiguous characters, Base32 ensures that encoded strings can be reliably read and transcribed by humans without error, which is particularly important for manual entry of TOTP secrets.
Base32 is used for TOTP (Time-based One-Time Password) secrets because it produces strings that are easy for humans to read and type if needed, safe to encode in QR codes, and unambiguous even when hand-copied. The RFC 4648 specification that defines Base32 was specifically designed for contexts where alphanumeric-only encoding is required.
Base32 output is approximately 60% larger than the input data. Specifically, for every 5 bytes of input, Base32 produces 8 characters of output (plus optional padding). This means the output length is ceil(input length × 8/5) characters, before any padding to make the output a multiple of 8.
Base32 itself only encodes binary data. To encode Unicode text, the text must first be converted to a byte sequence using an encoding like UTF-8. The resulting bytes are then Base32-encoded. When decoding, the Base32 output is converted back to bytes, and then those bytes are decoded from UTF-8 (or whatever encoding was used) to recover the original Unicode text.

Sources & References

Last updated: 2026-06-06

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Editorial Note

MyCalcBuddy Editorial Team

This page is maintained as an educational calculator reference.

Source

Formula Source: NIST Guide to SI Units

by National Institute of Standards

UpdatedLast reviewed: May 2026
CheckedFormula checks are based on standard references and internal QA review.