The most expensive way to discover a QR code doesn't scan is when 1,000 already-printed stickers are sitting in a box on your desk. Here's the five-minute test that catches the killers.
Print one at final size
Skip the "print on letter paper at desktop scale" instinct — print at the actual intended size on the actual intended paper stock. Glossy paper is more reflective. Cardstock has different texture. Vinyl behaves differently again. All of these affect scan reliability.
If you're ordering from a printer that does proofs, get a single-copy proof at full size before approving the run.
Test from real distance
Hold it where the customer will hold it. For a business card, that's 6-10 inches. For a tabletop menu QR, that's about 18 inches. For a yard sign, that's 6+ feet. The 1:10 rule says the QR should be about 1/10th of the scan distance; if testing shows a struggle, your QR's too small or contrast is too low.
Test on both iOS and Android
iPhones use Apple's native camera which is great with QR codes. Most Android phones in 2026 also have native camera scanning, but the algorithms differ slightly. Test on both if at all possible — and ideally with a 2-year-old phone (most users don't have flagships).
Test in real lighting
Indoor fluorescent. Outdoor direct sun. Outdoor shade. A dim restaurant. Phone cameras struggle in low light, and a barely-passing QR in good lighting will fail in dim conditions.
Test in real context
If the QR is on a wine bottle, test it on a wine bottle, not on a flat tabletop. Curved surfaces matter. Texture matters. Print it onto the actual surface or a sample.
Hand it to a stranger
Best test of all: hand it to someone who hasn't seen it before. If they pick up their phone and successfully scan within 5 seconds without instruction, you're good. If they ask "how do I open this?" — your real-world scan rate is going to be lower than you think.