A QR code only works if a person can stop, point a phone at it, and hold it steady for a second. Most placement failures break one of those three things. The code is too high, the person is moving, or the light bounces off the surface into the camera. This guide covers where codes go well, where they do not, and the size each spot needs.
Start with the person, not the surface
Before choosing a spot, picture the reader. Where are they standing? Are they walking, waiting or sitting? How far away is the code from their hands? The answer sets the size, the height and whether the placement works at all.
Do this
A code beside the till, at hand height, where a customer waits to pay and has ten seconds to spare.
Not this
A code on the ceiling-hung sign above the till, where nobody looks and nobody can reach.
Placement, distance and size
The size rule is simple: the code should be at least one tenth of the scan distance. The size and print guide explains why. The ruler below lets you try it.
About right for a table-top menu or a business card held at arm's length.
Here is the same rule applied to common spots.
| Placement | Typical scan distance | Minimum code size |
|---|---|---|
| Product packaging, held in the hand | 15 to 30 cm | 2 to 3 cm |
| Table talker, menu, counter card | 30 to 60 cm | 3 to 6 cm |
| Poster on a wall, eye level | 1 to 2 m | 10 to 20 cm |
| Shop window from the pavement | 2 to 4 m | 20 to 40 cm |
| Bus shelter or station board | 1.5 to 3 m | 15 to 30 cm |
| Parked vehicle, viewed from the kerb | 3 to 5 m | 30 to 50 cm |
| Screen in a waiting room or lobby | 2 to 4 m | 20 to 40 cm on the screen |
| Trade-show banner | 2 to 3 m | 20 to 30 cm |
Round up. Bigger is never a problem for the scanner.
Posters and wall signs
Put the code in the lower half of the poster, never the top corner. A person’s arm is more comfortable pointing slightly down than up, and a phone held below eye level does not block the face. Leave the code’s own width clear on every side, so the quiet zone is never crowded by headlines or photos.
Do this
An A2 poster with a 12 cm code in the lower third, a printed short URL beneath it and a clear margin around it.
Not this
A 4 cm code tucked into the top right of an A2 poster, 2 m above the floor, with the headline running into its border.
Worked example: a poster on a corridor wall, read by someone walking past at about 1.5 m. One tenth of 1.5 m is 15 cm. Print the code at 15 cm and put its centre at about 1200 mm from the floor.
Packaging
Packaging is scanned in the hand, so size is rarely the issue. Curves and folds are. Put the code on a flat panel, not across a seam, a crease or the curve of a bottle. Avoid the base of a box, which sits on a shelf where nobody can see it. The difficult surfaces guide covers curved and glossy packaging in detail.
Do this
A 2.5 cm code on the flat back panel of a carton, next to a line that says Scan for recipes.
Not this
A code wrapped around the shoulder of a bottle so the finder patterns sit on the curve.
Vehicles
A code on a van or a car is only scannable while it is parked. Nobody scans a moving vehicle, and a following driver should never try. Treat it as a poster seen from the kerb, at 3 to 5 m, and size it at 30 to 50 cm. Keep it on a flat panel, low enough to read but above the wheel arch where dirt collects.
Do this
A 40 cm code on the flat rear door of a van, with a call to action, scanned by a passer-by while it is parked outside a job.
Not this
A 10 cm code on the bumper, aimed at drivers behind in traffic.
Screens
A code on a screen is easy to scan if two things are true. It must be large enough on the viewer’s screen, at least 150 px wide on a phone or laptop, and much more on a TV in a lobby. And it must stay on screen long enough. A slide that changes every five seconds will lose most scans. Hold it for at least 15 seconds, or put the code in a fixed corner of every slide.
Do this
A 30 cm code on a lobby screen, fixed in the bottom right of every slide, read from 3 m.
Not this
A code shown for four seconds at the end of a 20-slide loop, then gone.
Screens also have brightness. A very bright display in a dark room can flare in the camera. Turn the screen brightness down a notch if the code will be scanned in dim conditions.
Windows and glass
Glass is the hardest common surface. The camera sees whatever is reflected in the window, often the street and the sky behind the reader. Three fixes work. Use matt, not glossy, vinyl. Place the code in the lower third of the glass, where reflections are of the pavement rather than the sky. Or put the code inside the shop on a small stand just behind the window, with a printed URL beside it for when the glare wins anyway.
Do this
A 25 cm matt vinyl code in the lower third of the shop window, angled away from direct sun.
Not this
A glossy sticker at head height on a south-facing window, invisible under the reflection of the sky from noon onward.
Common mistake
Putting the code on the inside of the glass but printing it as a normal, right-reading code. It then appears mirrored from the street. A few scanners cope with that; most do not. Print a mirror-image version for inside-glass use, then test it from the pavement.
Height: 900 to 1500 mm
Mount the centre of the code between 900 and 1500 mm from the floor. A seated wheelchair user can reach and photograph a code at around 1000 mm. A standing adult holds a phone comfortably at around 1200 to 1400 mm. The range covers both, and a child of ten. Above 1500 mm you lose seated readers; above 1800 mm you lose most people. The accessibility guide has more on reach and fallbacks.
Do this
A code at 1100 mm on a museum panel, reachable from a wheelchair and comfortable for a standing adult.
Not this
A code at 1900 mm above a doorway, chosen because the wall space was free.
Lighting
Cameras want even light on the code. Direct spotlights create hot spots that wash out the modules. Backlighting, where the light is behind the code and in the reader’s eyes, is worse. Shade and diffuse light are ideal. If the code is outdoors, check it at noon and at dusk, since each fails in a different way.
Do this
A code on a shaded wall under even shop lighting, checked in daylight and after dark.
Not this
A code directly under a picture light, with a bright reflection across the top-left finder pattern.
Try it in QR Studio
QR Studio can export the same code at several sizes in one go, so you can print the poster, the counter card and the window vinyl from a single design and know each one meets the distance rule.
Checklist
- Reader can stand still for ten seconds at this spot
- Scan distance measured from the furthest likely reader
- Code is at least distance ÷ 10, rounded up
- Centre of the code between 900 and 1500 mm from the floor
- Flat surface, not a seam, curve or fold
- Matt finish, or code placed in the lower third of any glass
- Even light, no spotlight or backlight on the code
- Screens: at least 150 px wide and on screen for 15 seconds or more
- Vehicles: sized for a parked view from the kerb, never for traffic
- Call to action and printed URL beside the code
- Tested in place, in the real light, with two phones
Try it yourself
Enter the scan distance for each spot on your list and note the minimum size. Then print the test sheet on the real material and check each spot in place.