Poster QR codes usually fail because they’re too small for the distance or placed where glare/shadows kill contrast. Here’s a practical sizing rule.
Rule of thumb (simple)#
A practical guideline: QR size ≈ scan distance ÷ 10. Example: if people scan from ~2 meters, aim for ~20 cm QR. If you’re unsure, go bigger.
Distance → recommended QR size#
Use the larger end if your payload is long (UTM-heavy links, big vCards) or the print quality is not perfect.
| Typical scan distance | Recommended QR size |
|---|---|
| 0.5 m (arm’s length) | 5–7 cm |
| 1 m (standing close) | 8–12 cm |
| 2 m (hallway / wall poster) | 15–25 cm |
| 5 m (big signage) | 40–60 cm |
Placement tips that matter#
- Put the QR on a flat, matte surface if possible (glossy reflections are scan killers).
- Keep a clean quiet zone (blank margin) around the QR — do not let background graphics touch the edges.
- Avoid heavy shadows and extreme angles. Keep it at a comfortable height (roughly chest/eye level).
- If the QR points to a URL, keep it short and stable (see: Short URL strategy).
Export for print#
Use SVG so edges stay sharp at large sizes. If you must use PNG, export high resolution and never upscale later. See: SVG vs PNG.
Fast test routine (do this once)#
- Print a test on the same material/finish.
- Scan on iPhone + Android under the real lighting.
- Test from the real distance (don’t test at 20cm if users will be 2m away).
- If it’s slow: increase size first, then simplify payload.