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How to use Base45 Encoder / Decoder

Pick Encode or Decode and enter your text. Encoding turns UTF-8 bytes into the RFC 9285 Base45 alphabet; decoding reverses it back to text.

Frequently asked questions

What is Base45?

A binary-to-text encoding from RFC 9285 that maps data onto 45 characters (0-9, A-Z, space and a few symbols). It is optimised to pack tightly into QR codes' alphanumeric mode.

Where is Base45 used?

Most famously in EU Digital COVID Certificates, where the payload is Base45-encoded before being placed in the QR code.

Why 45 characters?

QR alphanumeric mode has exactly 45 symbols; Base45 uses that full set so two bytes fit in three QR-friendly characters with no waste.

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