This tool [1] let me figure that out couple of years ago. And on the printable pages of the sites I own, for instance [2], I use a all caps domain and identifiers so that all my QR Codes are tiny (e.g: `HTTPS://ABC.DE/ABCD/42`, with up to 10 chars in the path).

[1]: https://www.nayuki.io/page/creating-a-qr-code-step-by-step [2]: https://www.brainzilla.com/logic/zebra/pdf/blood-donation.pd...