The most common question when someone is about to print a QR Code: "how big does it need to be?" And the right answer isn't "X centimeters" — it depends on the distance it will be scanned at.
The rule that works in 99% of cases:
QR size = reading distance ÷ 10
Want to scan from 30cm (restaurant table)? QR needs at least 3cm × 3cm. Billboard from 10m? 1m × 1m. T-shirt read from 1m? 10cm × 10cm.
That 1/10 leaves room for bad phones, weak lighting and slight printing blur. If you want to be conservative, use 1/8 (slightly larger QR). If you want to push it, 1/12 works in good conditions.
Reference table by use case
| Use case | Distance | Minimum size |
|---|---|---|
| Restaurant table | 30 cm (1ft) | 3 cm (1.2in) |
| Business card | 30 cm | 2.5 cm (1in) |
| Small packaging (cosmetics, pet food) | 40 cm | 4 cm |
| Storefront sticker | 1-2 m | 10-20 cm |
| T-shirt / uniform | 1 m | 10 cm |
| Event banner | 2-3 m | 20-30 cm |
| Wall poster | 2-3 m | 25 cm |
| Billboard / facade | 10 m | 1 m |
| Bus advert (moving vehicle) | 5-10 m | 40-100 cm |
Common mistakes that kill reading
1. QR too small on a table
The restaurant menu with a 2cm × 2cm QR is a classic. Works on iPhone 13 with a good camera, fails on mid-range Android. Result: 30% of customers can't scan and give up. Absolute minimum for a table: 2.5cm, recommended 3-4cm.
2. Not testing before printing 500 copies
We've seen entire franchise chains recall 2000 menus due to a wrong QR. Before sending to the printer:
- Print 1 copy at home.
- Scan with 3 different phones: iPhone, premium Android, mid-range Android.
- Test in low light (bar table at night, storefront in the afternoon).
- Test with a slight blur (run your finger over the QR to see if it still reads).
3. Insufficient contrast
QR Code needs high contrast between dark cells and the background. Pure black on pure white is ideal. Light gray and dark gray doesn't work. Dark color on light color works if the contrast is strong (navy on yellow, yes; navy on purple, no).
The QR can only be inverted (light on dark background) if your platform exports correctly — some scanners fail with inverted QR.
4. White margin cropped
Every QR has a "quiet zone" — a white border around it. Don't cut that border, even if it looks like wasted space. Without it, the scanner can't find where the QR starts.
The standard margin is 4 white cells on each side (≈ 10% of the QR size). If you want to make it more compact, you can reduce to 2 cells, but test well.
5. Excessive curvature
QR on a curved surface (beer can, mug, bottle) works up to ~30° curvature. More than that, scanners fail. For a soda can, prefer a small QR (1.5cm) in the "flattest" area.
Ideal size vs minimum size
The 1/10 rule gives the minimum. For a good experience, use 1.5× to 2× that — the customer scans faster, with less hesitation.
On a restaurant table: minimum 3cm, ideal 5-6cm. On a 2m storefront: minimum 20cm, ideal 30cm.
QR version matters too
QR Code has versions 1 through 40. The more data (long URL, vCard), the higher the version and the denser the cells. High version at small size = unreadable.
Tip: use dynamic QR (code2scan.com/q/abc has ~25 characters) instead of embedding a huge URL. QR comes out at version 2-3 (well readable) instead of version 10+. Here's the dynamic vs static QR guide.
To stop making mistakes
- Calculate the real reading distance for your case.
- Divide by 10 → minimum size.
- Print and test on 3 phones + weak light.
- Use dynamic QR (short URL) whenever possible.
In doubt: bigger is always better. A 5cm QR instead of 3cm doesn't ruin the design and eliminates reading problems.
Create your QR and export in PNG/SVG at the right resolution.
