QR codes by setting
The technology does not change from one industry to the next. The reading distance, the surface and the abuse it will take do — and those decide everything else.
A QR code is the same technology everywhere. What changes from one setting to the next is the reading distance, the surface it is printed on, and what happens to it afterwards — and those three things decide the size, the error-correction level and the finish.
Below are ten settings we get asked about most, each with the numbers that actually apply and the mistake that most often ruins the job. Every one links to a longer guide.
The numbers at a glance
| Setting | Read from | Code size | Level |
|---|---|---|---|
| Business card | 20 cm | 20–25 mm | M |
| Product label | 20 cm | 20–25 mm | H |
| Restaurant table card | 30 cm | 35–40 mm | M |
| Flyer or invitation | 25–30 cm | 25–40 mm | M |
| Hotel room card | 30 cm | 35–50 mm | M |
| Shop window | 1–1.5 m | 100–150 mm | M |
| Estate agent board | 3 m | 300 mm | H |
| Exhibition banner | 2 m | 200 mm | M |
| Shipping carton | 50 cm | 50 mm | H |
| Roadside sign | 10 m | 1 m | H |
Where those numbers come from, and when to break them, is in the printing size guide and error correction explained.
Restaurants and cafés
A table card pointing at a menu page you can edit — not a PDF, and not a third-party service that can lapse.
The mistake to avoid: Overhead lighting plus a glossy laminate puts a reflection over the symbol at exactly the angle a seated guest holds a phone. Matt lamination costs the same and fixes it.
Full guide: QR Codes for Restaurant Menus
Retail and product packaging
Product information, provenance, recycling instructions and increasingly the digital labelling that regulation is starting to require.
The mistake to avoid: The most common cause of a dead retail code is a price gun or promotional label landing on top of it. Agree the placement with whoever applies them before the artwork is signed off.
Full guide: QR Codes for Product Packaging
Estate agents
A direct link to the individual property, not the agency homepage. Someone standing at the gate is the warmest lead that listing will ever get.
The mistake to avoid: Boards are read from the pavement, three metres away, which the 10:1 rule turns into a 300 mm code. Most agency boards carry one around 70 mm, sized for a distance nobody stands at.
Full guide: QR Codes for Real Estate Signs
Business cards and networking
A link to a contact page beats an embedded vCard almost every time, because a full vCard is too dense to scan at the size a card allows.
The mistake to avoid: A complete vCard is 250–400 bytes, which at 20 mm gives a module width below the floor for reliable phone scanning. Point at a page that serves the .vcf instead.
Full guide: QR Codes for Business Cards
Hotels and hospitality
Guest WiFi, room service, local recommendations and check-out — the codes a guest uses most are the ones in the room, not in the lobby.
The mistake to avoid: Put WiFi codes on a separate guest network. A printed code is a printed password, and anyone who photographs the card keeps it permanently.
Full guide: How to Create a WiFi QR Code
Events, weddings and ticketing
One code on the invitation pointing at a page with RSVP, directions, accommodation and, afterwards, the photographs.
The mistake to avoid: The finishes that make stationery beautiful — foil, deep letterpress, dark stock — are the ones that stop codes scanning. Print the code flat, on a light plate.
Full guide: QR Codes for Wedding Invitations
Local services and trades
A review code on the job sheet, handed over at the moment the work is finished and the customer is happiest.
The mistake to avoid: Never offer a discount in exchange for a review, and never survey customers to decide who gets asked. Both are against Google's policies and both can get a profile penalised.
Full guide: QR Codes for Google Reviews
Print, marketing and flyers
One code, one promise, one landing page — and a separate short path per channel so you can count scans without renting a dynamic code.
The mistake to avoid: Coloured stock is where flyer codes fail. What matters is luminance contrast, not how different the colours look; convert the design to greyscale and see whether the code survives.
Full guide: QR Codes for Flyers
Manufacturing and 3D printing
Serial numbers, maintenance records and documentation moulded or printed into the part itself, with no label to fall off.
The mistake to avoid: With a 0.4 mm nozzle a module needs about 2 mm to come out square, so payload length translates directly into physical size. A short redirect is not a nicety here.
Full guide: QR Codes for 3D Printing
Education and public institutions
Reading lists, lab instructions, museum labels, notice boards — places where the audience has every kind of phone and no patience for an app.
The mistake to avoid: Institutional codes outlive the websites behind them. Point them at a short path you control so a site rebuild does not orphan every sign in the building.
Full guide: Why QR Codes Stop Working
The two decisions that apply everywhere
Point the code at a short path on your own domain. Not at a deep URL that will change in the next site rebuild, and not at a third-party dynamic service that can stop resolving. One redirect rule then fixes any future move, for every code you have ever printed. The reasoning is in static versus dynamic QR codes.
Test the printed proof, not the file. On the real stock, at the real distance, in the real light, on the oldest phone available. Almost everything that goes wrong is visible at that point and invisible before it. The pre-print checklist takes ten minutes.