Base32 vs Base64: when bigger overhead is the better choice
Base64 for machine-to-machine data exchange. Base32 for anything a human will type, read, or transcribe. The overhead difference (33% vs 60%) is negligible for the small payloads (a few dozen bytes) where human readability matters.
Base64 packs 6 bits per character and expands data by 33%. Base32 packs 5 bits per character and expands data by 60%. Base32 seems strictly worse, but it has one critical advantage: it's case-insensitive and avoids visually confusable characters. For data that humans type or read aloud, Base32's extra overhead is worth the usability gain.
By TechCompare · Updated
How this is calculated
Base32 is used for OTP secrets (the 16-character codes you type into Google Authenticator), product license keys, and recovery codes. The RFC 4648 Base32 alphabet excludes 0, 1, 8, and 9 to avoid confusion with O, I/l, B, and g/q. Base64's alphabet includes letters in both cases, digits, +, and /, making it error-prone for human transcription. If a user is going to type the encoded value, Base32. If machines are exchanging it, Base64.
Verdict
Base64 for machine-to-machine data exchange. Base32 for anything a human will type, read, or transcribe. The overhead difference (33% vs 60%) is negligible for the small payloads (a few dozen bytes) where human readability matters.