One of the most common mistakes when printing a QR code is making it too small. On your computer screen it looks perfect, but once printed on a card or poster, phones cannot read it. The right size mainly depends on two factors: the distance it will be scanned from and the amount of information it contains. In this guide we give you simple rules so you always get it right.
The distance rule: 10 to 1
The most useful rule is the 10:1 ratio: the code should be at least one tenth of the distance it will be scanned from.
- Scanned from 20 cm (8 in): the code should be at least 2 cm (0.8 in) wide.
- Scanned from 1 meter (3 ft): at least 10 cm (4 in).
- Scanned from 3 meters (10 ft): at least 30 cm (12 in).
This rule works well in normal lighting with codes of medium density. If the environment is dim or the code is very dense, increase the size by 20 to 30%.
Recommended sizes by medium
| Medium | Typical distance | Recommended minimum size |
|---|---|---|
| Business card | 15-25 cm | 2 × 2 cm (0.8 in) |
| Flyer | 20-30 cm | 2.5 × 2.5 cm (1 in) |
| Product label | 15-30 cm | 2 × 2 cm (0.8 in) |
| Restaurant table card | 30-40 cm | 3 × 3 cm (1.2 in) |
| A3 / tabloid poster | 1 m | 10 × 10 cm (4 in) |
| Shop window | 1-2 m | 15 × 15 cm (6 in) |
| Billboard | 5 m or more | 50 × 50 cm (20 in) or more |
For the smallest medium, such as a business card, do not go below 2 cm. Below that size many phones will struggle, especially budget models.
Code density matters too
A QR code has more or fewer modules depending on how much information it stores. A short URL produces a code with a few large modules; a long URL or a full vCard produces many small modules. At the same printed size, each module will be smaller and harder to distinguish.
Tips to reduce density:
- Use short URLs. Avoid unnecessary long parameters.
- In a vCard, include only the essential details.
- Use an appropriate error correction level: level H adds lots of modules; use it only if you include a logo.
- Consider a dynamic code, which contains a short URL and produces a cleaner pattern.
Do not forget the quiet zone
The quiet zone is the white margin around the code. The standard recommends a margin equal to 4 modules. If your poster or label design intrudes on that margin with text, colors or images, the scanner may not find the code. When working out how much space it will take in your layout, add that margin to the code size.
Resolution and file format
For printing, the format matters as much as the size:
- SVG, PDF or EPS: vector formats. They can be scaled to any size without losing sharpness. They are the best option for print.
- PNG: if you use it, make sure it has enough resolution, at least 300 dpi at the final size. A small PNG enlarged will look blurry and module edges will lose definition.
With the QRcrea QR code generator you can download your code as SVG, PDF and high-resolution PNG.
Factors that affect scanning
Besides size, keep in mind:
- Contrast: dark modules on a light background. A light gray QR code on white will need to be larger to be read.
- Material: glossy or laminated paper can cause glare. A matte finish is preferable.
- Curved surfaces: on bottles or cans, place the code on the flattest area and do not make it too wide.
- Lighting: in dark places, increase size and contrast.
- Placement height: on posters, put the code between 1 and 1.5 meters (3-5 ft) from the floor, at hand height.
Always do a printed test
Before printing hundreds of copies, print a proof at the real size and scan it with several phones, at the distance your customers will use and in the lighting of the place where it will go. It is the only way to be sure.
Quick calculation examples
Imagine a poster in a shop window that people will see from the sidewalk, about 2 meters (6.5 ft) away: the code should be at least 20 cm (8 in) wide. For a counter display at about 50 cm (20 in), 5 cm (2 in) is enough. For a sticker on the side of a van that someone might scan from 3 meters (10 ft), you will need about 30 cm (12 in). And on a restaurant table card, 3 or 4 cm (1.2-1.6 in) is more than enough. If you are torn between two sizes, always choose the larger one: a slightly bigger code never causes scanning problems, but a small one does.
Placement checklist
Before you print, check that the code sits on a flat, matte area, that nothing invades its white margin, that it is at a comfortable height for the people who will scan it and that there is enough light in that spot. These four checks, together with the right size, prevent the vast majority of scanning problems.
Frequently asked questions
What is the absolute minimum size of a QR code?
In practice, 2 × 2 cm (0.8 in) is the recommended minimum for general use. Smaller codes exist, but they need very short content, high-quality printing and powerful scanners.
Is a bigger code always better?
Up to a point. A huge code at short range forces people to step back to frame it. Match the size to the real scanning distance.
Can I put a QR code on a T-shirt or fabric?
Yes, but fabric wrinkles and distorts the code. Make it larger than usual, with high contrast, in an area that stays flat.
Conclusion
The right QR code size depends on scanning distance and density. Remember the 10:1 rule, do not go below 2 cm, respect the quiet zone, use vector formats and always do a printed test. Follow these guidelines and your codes will scan first time. Create yours for free with the QRcrea generator and download it ready for print.
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