SMS draft QR — Settings and quality

Worked example

A 43-byte SMS payload fits 37 x 37 at high error correction; keep square or lightly rounded modules and contrast above 4.5:1.

Drop to level M and the same payload fits 33 x 33, a saving of four modules per side, but the Chatcument mark in the center is then closer to the limit of what the code can lose. With a short message there is little reason to trade away safety, so choose M only for a tiny sticker and test it printed.

Module shape matters at small sizes. Square modules and square markers give the sharpest edges. Dots, rounded or extra-rounded shapes look softer but shrink the contact area between neighbouring modules, so on a 2 to 3 cm table sticker keep Classic or a rounded preset with a darker colour and verify with an older phone.

A common mistake is selecting a gradient whose end colour is pale. The contrast check compares the dark colour, the marker colour and the gradient end against the background, and the lowest one must reach 4.5:1 or the export is blocked. Fix it by darkening the end colour, or turn the gradient off for the smallest prints.

Concrete check: at 720 px with the 18 px border, a 37-module code has modules of about 18.5 px. Raise the size to 1000 or more only for large signage, and keep the quiet border near 18 to 24 px so the white margin stays visible around the pattern.

Example recipient + short draft

SMS draft action

Short messages let you keep maximum error correction at no real cost in grid size.