Which Base32 alphabet does this tool use?

The RFC 4648 standard alphabet: A=0, B=1, … Z=25, 2=26, 3=27, 4=28, 5=29, 6=30, 7=31. Lowercase input is automatically uppercased. Padding characters (=) and spaces are stripped before conversion.

Can it handle very long Base32 strings?

Yes. The converter uses JavaScript BigInt arithmetic, so there is no practical length limit. Strings hundreds of characters long are handled without loss of precision.

Is this the same as Base32 decoding?

Not exactly. Standard Base32 decoding (RFC 4648) treats the input as encoded bytes and produces binary data. This tool treats the Base32 string as a pure positional integer and gives you its numeric value — similar to how you would read a hexadecimal number as an integer.

Why do some characters produce an error?

The RFC 4648 Base32 alphabet only includes A-Z and 2-7. Characters like 0, 1, 8, 9, and any punctuation are not valid Base32 digits and will trigger an error. The tool highlights the offending character so you can fix it quickly.

Base32 to Decimal Converter

Name: Base32 to Decimal Converter
Availability: InStock
Author: Nham Vu

Paste a Base32 string (A-Z, 2-7) and instantly see its decimal integer value.

Base32 Input

Base32 string (A–Z, 2–7)

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

Enter a Base32 string on the left and click Convert.

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Summary

Paste a Base32 string (A-Z, 2-7) and instantly see its decimal integer value.

How it works

Type or paste your Base32 string into the input field.
Each character is mapped to its 5-bit value: A=0, B=1, ..., Z=25, 2=26, ..., 7=31.
The tool multiplies the running total by 32 and adds each digit value left-to-right.
The final decimal integer is displayed along with the equivalent hex and binary representations.
Click "Copy" next to any result to copy it to your clipboard.

Use cases

Decode TOTP secret keys stored as Base32 integers for debugging.
Convert Base32-encoded identifiers used in URL shorteners to their numeric IDs.
Verify Base32 encoding implementations by checking the expected integer output.
Explore positional notation and understand how Base32 relates to binary and decimal.
Inspect Base32 values produced by Crockford or RFC 4648 encoders.
Convert Base32 hash fragments to decimal for database lookups.

Frequently Asked Questions

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Last updated: 2026-05-29 · Reviewed by Nham Vu