QR code sizing and printing: the numbers that matter

A QR code that scans on your monitor can still fail on paper. Print introduces size, distance, lighting, and ink, and each one has a number attached. These are the numbers.

2 x 2 cm: the floor for handheld scanning

For a code scanned at arm's length, print at least 2 x 2 centimeters (about 0.8 inches). Below that, older phone cameras struggle to resolve the modules, and any printing blur eats your margin. When in doubt, go bigger.

The 10:1 distance rule

Take the farthest distance a person will scan from, and divide by 10. That is your minimum code width.

• A table tent scanned from 30 cm needs a code at least 3 cm wide.
• A poster read from 3 meters needs at least 30 cm.
• A banner scanned from 10 meters across a hall needs a full meter.

The rule comes from how many pixels of the pattern a phone camera captures at distance. Codes with more content need more modules, which makes each module smaller, so dense codes need to be larger still. One more reason short links beat long URLs in a pattern.

4 modules of quiet zone

The QR spec requires a margin of empty space around the pattern: the quiet zone, 4 modules wide on all four sides. A module is one of the small squares in the pattern, so the margin scales with the code.

Designers crop it because it looks like wasted space. Scanners need it to find the pattern's edges. Keep the margin, and keep it the same color as the code's background. A code dropped onto a busy photo or a dark page with no margin fails for exactly this reason.

Error correction: L, M, Q, H

QR codes carry redundant data so damaged patterns still scan. Four levels set how much of the code can be lost and recovered:

• L recovers about 7 percent. Largest capacity, most fragile.
• M recovers about 15 percent. The usual default.
• Q recovers about 25 percent.
• H recovers about 30 percent. Use it for codes with a logo, since the logo covers modules exactly like damage would.

Higher levels add modules, which makes the pattern denser, which pushes your minimum print size up. Pick the level your situation needs and no more. When you add a logo in the QR Tool designer, it switches the code to H on its own.

Contrast and color

Scanners want a dark pattern on a light background. Brand colors are fine as long as that stays true; a deep purple on white scans, pale yellow on white does not. Light-on-dark inverted codes fail on some readers, so inverting is a risk you accept. Our designer warns you when a color pair will not scan reliably.

Resolution: vector beats pixels

Raster exports need at least 300 DPI at the final printed size, so a 1024-pixel PNG covers a code up to about 8.7 cm wide. Past that, export vector. An SVG or PDF scales from a sticker to a billboard with edges that stay sharp. We export PNG, SVG, and PDF on every plan, free included.

Print one proof first

Before the full run, print a single proof at final size on the real material. Scan it with an iPhone and an Android, from the real distance, in the real lighting. The proof costs one sheet of paper; the reprint costs the whole run.