Michael Haren’s Wassupy Blog

A tiny improvement to your QR Codes

in technology

Regardless of your executive’s enthusiasm, QR codes are not a silver bullet. But they are occasionally useful and I learned that you can improve them with a small tweak: leverage the right mode.

Suppose you encode a URL, e.g. https://www.wassupy.com/:

A qr code that is 33x33 blocks

And then this similar URL, HTTPS://WWW.WASSUPY.COM/:

A 2nd, smaller qr code that is 29 by 29 blocks

The all-caps version is simpler because it makes use of the “alphanumeric” segment mode to attain higher information density:

Input mode Bits/char. Character set
Numeric 3 ⅓ [0-9]
Alphanumeric 5 ½ [0–9A–Z$%*+./: -]
Binary/byte 8  

Note: the alphanumeric set does not include lowercase letters.

When building the QR code, your input is split into segments according to what mode can handle the input, and all-caps URLs fit into the more efficient alphanumeric mode. Keeping this in mind, you can generally always make the scheme and host portion of a URL uppercase, and the more caps you can accommodate in the path, the better.

Of course, using shorter URLs helps the most 😊.