The Fundamental Size Rules
Before diving into specific formats, two numbers anchor everything else in this guide.
Absolute minimum: 1 cm × 1 cm. This is the theoretical floor - the smallest size at which a modern phone camera can decode a QR code under ideal conditions: perfect lighting, a simple low-data code, a camera held very close and very steady. In practice, you should never actually print at this size because real-world conditions are never ideal.
Practical minimum: 2 cm × 2 cm. At 2 cm square, a standard QR code scans reliably on any modern smartphone in normal indoor lighting when held 15-25 cm away. This is the floor for anything that will actually be used by a real person. For product labels, receipts, and small print collateral where you have limited space, 2 cm is your minimum. Anything smaller is a gamble.
The Scanning Distance Formula: The 1:10 Ratio
Here is the single most useful rule in QR code sizing: print the code at 1 cm for every 10 cm of scanning distance.
That means if you expect someone to scan from 30 cm away (roughly arm's length, which is typical for a leaflet or a product on a shelf), the code should be at least 3 cm square. If you expect someone to scan from 2 metres away - say, a poster at a trade show booth - the code needs to be at least 20 cm square.
This ratio is a minimum, not a target. When in doubt, go larger. A bigger QR code never fails to scan because it is too easy to read. A smaller one might fail entirely.
Size Recommendations by Print Format
| Format | Typical Scanning Distance | Recommended Size | Minimum Size |
|---|---|---|---|
| Business card | 20-30 cm | 20 mm × 20 mm | 18 mm × 18 mm |
| Flyer / A5 leaflet | 30-40 cm | 35 mm × 35 mm | 25 mm × 25 mm |
| A4 poster | 40-60 cm | 50 mm × 50 mm | 35 mm × 35 mm |
| A3 poster | 60-100 cm | 80 mm × 80 mm | 60 mm × 60 mm |
| A2 / large event poster | 1-1.5 m | 120 mm × 120 mm | 90 mm × 90 mm |
| Product label | 20-30 cm | 20 mm × 20 mm | 15 mm × 15 mm |
| T-shirt / apparel print | 40-80 cm | 60 mm × 60 mm | 45 mm × 45 mm |
| Billboard / large format | 3-10 m | 300 mm × 300 mm + | 300 mm × 300 mm |
Business Cards
A standard business card is 85 mm × 55 mm, which gives you limited real estate. A 20 mm × 20 mm code on the back of the card is the sweet spot - large enough to scan easily but small enough to leave room for branding or additional contact details. Position it in a corner with clear quiet zone space around it. Never let background artwork butt up against the code edge.
Flyers and A5 Leaflets
Flyers are typically read at arm's length, so 35 mm square is a comfortable target. You have the space, so use it. A larger code on a flyer also draws the eye more naturally than a tiny one tucked in a corner. Pair it with a short call-to-action label directly below or beside the code to maximise scan rates.
Posters
Poster QR codes often underperform because designers think about how the poster looks on a wall rather than how a person interacts with it. The question to ask is: how close will someone realistically get before they decide to scan? For a poster on a wall in a café, people might walk up to 30-40 cm away. For a poster behind a counter, the minimum distance might be 1.5 metres. Use the 1:10 rule to calculate accordingly, then add 20% for safety.
Billboards
Billboard QR codes are contentious. The scanning distance problem is real - if your billboard is on a motorway, no one is safely stopping to scan it. But for static pedestrian locations (bus shelters, building facades in a city center, shopping mall displays) they can work well. For a billboard viewed from 5 metres, the code needs to be at least 50 cm × 50 cm. Many effective billboard QR codes run at 80-100 cm square. Go large or do not bother.
Product Labels
Product labels are scanned at close range, so 20 mm works in most cases. The bigger challenge on labels is often the quiet zone - when a label has a busy background right up to the edge of the allocated code space, scan failure rates climb. Always allocate a clean white box for the code that is at least 4 module-widths larger than the code on every side.
T-Shirts and Apparel
A scannable QR code on a t-shirt is a legitimate marketing tool for events, festivals, and brand activations. The practical challenge is that the wearer is moving and the fabric can distort slightly. Use error correction level H (30%), size up to at least 60 mm square, and test the finished print before the event. A high-contrast print (black on white, or white on a dark substrate within a white box) is essential.
Resolution Requirements: Screen vs Print
Resolution is where many people go wrong when moving from screen to print.
Screen display typically runs at 72-96 PPI (pixels per inch). At these resolutions, a 500px × 500px image looks fine on a monitor. But send that same file to a printer and the result will be soft and blurry, because print requires much higher pixel density.
Print standard is 300 DPI (dots per inch). This means that for every physical inch of printed output, the printer wants 300 pixels of image data. A QR code printed at 25 mm × 25 mm (approximately 1 inch square) needs to be at least 300px × 300px to print sharply. A code printed at 50 mm × 50 mm (approximately 2 inches) needs 600px × 600px minimum.
For practical purposes, the safest approach is to always use the highest resolution file available and let the layout software scale it down. More pixels than needed is never a problem. Too few pixels is always a problem.
Why Downloading at 1024px from Vexifa Matters
Vexifa QR Code lets you download your code as a 1024px × 1024px PNG. Here is why that specific size is useful:
- At 300 DPI, 1024px of image data covers approximately 86 mm of physical print size - large enough to reproduce crisply at the size needed for most posters and print collateral without upscaling.
- For smaller outputs like business cards (20 mm) or product labels (20 mm), the printer downscales from 1024px to roughly 240px, which is still above the 300 DPI threshold and produces a sharp result.
- The PNG format preserves the hard edges of every QR code module without compression artefacts, which matters for reliable scanning.
If you need a QR code for a billboard or large-format print exceeding 100 mm at 300 DPI, work with a vector-capable format. While Vexifa outputs PNG, you can place the 1024px file and let a professional large-format print bureau handle the upscaling - most modern RIP software handles this well, or you can trace the PNG to an SVG using free tools like Inkscape.
Quick Reference: Minimum QR Code Sizes
- 1 cm × 1 cm - absolute theoretical minimum, not recommended for real use
- 2 cm × 2 cm - practical minimum for close-range scanning (labels, receipts)
- 2-3 cm - business cards
- 3.5-5 cm - flyers and A5 leaflets
- 5-8 cm - A4 to A3 posters
- 10-30 cm+ - large posters and event displays
- 30 cm+ - billboards (pedestrian locations only)
Frequently Asked Questions
Is there a maximum size for a QR code?
No. A QR code can be any size - there is no upper limit. The only practical constraint is that very large printed codes, such as those painted on floors or sides of buildings, need to be scanned from a correspondingly large distance. As long as the camera can frame the entire code, it will scan.
Does a larger QR code scan faster?
In practice, yes - a larger code is easier for the camera's autofocus to lock onto and for the decoder to process. The difference in decode speed is small on modern phones but real, especially in lower-light conditions.
Can I resize a QR code image after downloading it?
You can scale it down without quality loss because you are reducing the number of pixels needed. Scaling it up using standard image resizing (bicubic, bilinear) will introduce blur. If you need a much larger output than the source file supports, either re-download at a higher resolution or convert the PNG to SVG before scaling.
Why does my printed QR code look blurry?
Almost always, this is a resolution issue. The image file did not contain enough pixels for the physical print size requested. Download the 1024px PNG from Vexifa and ensure your design file is set to 300 DPI before placing the image. If the code still looks soft, the issue may be the printer settings or a JPEG conversion that introduced compression artefacts - always use PNG for QR codes.
Does the complexity of the QR code affect the minimum scan size?
Yes. A code encoding a long URL or a vCard with many fields has more modules (tiny squares) in the pattern, making each individual module smaller at any given print size. More complex codes need to be printed slightly larger to remain reliably scannable. Keep encoded data short to keep the code pattern simple and scan-friendly at smaller print sizes.