QR Code Print Size Checker

The model, written out

Everything on this page comes from four lines of arithmetic. They are published here so you can check them rather than take our word for it.

1. Module grid. A version v symbol is 4v + 17 modules across. The version is whatever the encoder chose for your content at your error-correction level.
2. Total grid. Add the quiet zone on both sides: total = 4v + 17 + 2q, where q is 4 by default.
3. Module size. module_mm = printed_width_mm ÷ total. This is the number that decides everything.
4. Verdict. Compare module_mm against the floor and the comfort threshold for your print method, listed in the table above.

Scan distance uses the 10:1 rule: max_distance ≈ 10 × symbol_width, measured on the symbol itself rather than the quiet zone. Raster export size is px = (width_mm ÷ 25.4) × dpi, rounded up so the total grid divides it exactly — otherwise some modules land one pixel wider than their neighbours and the edges soften.

Why higher error correction can make things worse

It is natural to assume that level H — the one that recovers 30% — is the safe choice for a small printed code. It usually is not. Error-correction codewords are data, and more data means a higher version, and a higher version means more modules squeezed into the same printed square.

A 90-character URL at level M lands around version 6 (41×41). The same URL at level H needs roughly version 9 (53×53). Printed at 25 mm, the modules go from about 1.4 mm to about 1.1 mm — a 20% reduction in the dimension that decides whether the code reads at all. You bought redundancy and paid for it in legibility.

The quiet zone is not optional

The four-module white border is part of the specification, and it is what lets a decoder find the symbol's edge in a photograph. Designers trim it constantly, because on screen the code still scans and the layout looks tighter. On paper, against a coloured background, at an angle, in poor light, it stops working — and the failure is intermittent, which is the worst kind.

Keep four modules, and keep them the same colour as the code's background. At the sizes in the table above, that is between 2 mm and 5 mm of clear space.

A checklist before the file goes to print

• Module size is at or above the comfort threshold for your print method.
• Quiet zone is four modules, clear of other artwork.
• Dark modules on a light background — never inverted.
• Contrast at 7:1 or better between the two colours.
• Exported as SVG, or as PNG at 300 dpi with a snapped pixel size.
• Scanned from the actual proof, at the actual distance, on at least two different phones.
• Scanned again after lamination or varnish — a gloss finish reflects the flash straight back into the lens.