Base32 vs Base64: What the Difference Is and When to Use Each

Base32 and Base64 both turn any data into plain text characters, so it can travel through systems that only handle text. They are encodings, not encryption: anyone can reverse them.

How they differ

• Base64 uses 64 characters: capital and small letters, numbers, plus and slash. Every 3 bytes become 4 characters, so the text is about 33 percent bigger.
• Base32 uses 32 characters: the capital letters A to Z and the numbers 2 to 7. Every 5 bytes become 8 characters, so the text is about 60 percent bigger.
• Both pad the end with equals signs so the length comes out right, though padding is often left off.

Why choose Base32

Base32 leaves out characters that are easy to mix up, such as 0 and O, or 1 and I, and it has no lower case, so it survives being read aloud, typed by hand or stored in systems that ignore case. That is why the secret keys in authenticator apps are shown in Base32, and why it appears in file names and some ID formats. The Base32 Encoder supports the standard alphabet, the extended hex one and the Crockford variant, which is designed to be easy to read.

Why choose Base64

Base64 is more compact, so it is the usual choice for email attachments, data URLs, and tokens in web requests. A URL-safe version swaps plus and slash for dash and underscore. The Base64 Encoder handles both the normal and URL-encoded forms.

How to choose

1. Will a person read, type or say it aloud? Use Base32.
2. Does size matter, and is it only for machines? Use Base64.
3. Is it going in a web address? Use the URL-safe Base64 form.
4. Do you need to keep it secret? Neither one helps. Use real encryption.