QR Code Size Calculator
Calculate the minimum QR code size for reliable scanning at any distance. Based on the 10:1 scanning ratio.
Scanning Distance
Minimum Size
minimum recommended size
This calculator uses the 10:1 ratio: the QR code should be at least 1/10th of the scanning distance. For printed materials or challenging conditions (poor lighting, angled viewing), consider increasing the size by 20-50%.
How to calculate QR code size
The minimum size of a QR code is determined by the distance at which it will be scanned. Use the 10:1 ratio: the QR code's width should be at least 1/10th of the scanning distance. This rule of thumb is widely used in print and signage and ensures reliable scanning across phone cameras of varying quality.
This isn't an arbitrary rule. QR codes are defined by the international standard ISO/IEC 18004, which specifies symbol structure, encoding, and error correction. Scanning reliability depends on the camera being able to resolve individual modules (the small squares that make up the code). The 10:1 ratio gives modern smartphone cameras enough resolution to decode the symbol from typical viewing distances.
The formula
Both values must be in the same units. If your scanning distance is in metres, your minimum size will also be in metres. Convert as needed (1 metre = 100 cm = 39.37 inches).
Worked example
You're printing a QR code on a poster that will be displayed in a hallway. People will typically scan it from 1.5 metres away (150 cm).
- 1. Scanning distance: 150 cm
- 2. Apply the 10:1 ratio: 150 ÷ 10 = 15 cm
- 3. Minimum QR code width: 15 cm
For challenging conditions (low light, glare, angled viewing) or older devices, increase by 20-50%. So 15 cm becomes 18-22 cm. Always test scanning before committing to a print run.
Quick Reference Chart
| Use Case | Scan Distance | Min. Size |
|---|---|---|
| Business card | 15-30cm | 1.5-3cm |
| Flyer / Brochure | 30-50cm | 3-5cm |
| Poster (A3/A2) | 1-2m | 10-20cm |
| Banner / Sign | 3-5m | 30-50cm |
| Billboard | 10-20m | 1-2m |
| Product label | 10-20cm | 1-2cm |
| Table tent | 30-60cm | 3-6cm |
| Window display | 1-3m | 10-30cm |
Tips for Reliable Scanning
Quiet Zone
Leave white space around your QR code equal to 4 modules (the small squares). Most generators handle this automatically.
Contrast
Dark foreground on light background works best. Avoid low contrast colour combinations. Black on white is most reliable.
Print Resolution
For print, use 300 DPI minimum. Export as SVG for perfect scaling at any size, or use high-resolution PNG.
Frequently Asked Questions
What is the minimum size for a QR code?
The minimum QR code size depends on scanning distance. The widely accepted 10:1 rule says the QR code should be at least 1/10th of the scanning distance. For close-range scanning (15-30cm) the minimum is around 1.5-3cm. For posters scanned at 1-2 metres the minimum is 10-20cm. Use the calculator above for precise sizes.
What is the 10:1 rule for QR codes?
The 10:1 rule states that the minimum QR code size should be 1/10th of the scanning distance. For example, if users will scan from 1 metre away, the QR code should be at least 10cm. This ensures reliable scanning across different devices, including older phones with lower-resolution cameras.
What size should a QR code be in pixels?
For digital use, a QR code should be at least 300x300 pixels for reliable scanning on most screens. For print, calculate the physical size first, then multiply by 300 DPI for high-quality print or 150 DPI for large-format viewed from distance. Always export as SVG when possible for perfect scaling.
What happens if my QR code is too small?
QR codes that are too small may fail to scan or require users to get uncomfortably close. Older phones with lower resolution cameras are especially affected. When in doubt, go larger. The cost of a slightly larger code is far less than the cost of a code that does not scan reliably.
What size should a QR code be on a business card?
For business cards, a QR code should be at least 1.5-2cm (0.6-0.8 inches). Business cards are scanned at close range (15-30cm), so the 10:1 rule gives a minimum of 1.5-3cm. Leave at least 4mm of quiet zone (white space) around the code.
What size should a QR code be on a poster?
For posters scanned from 1-2 metres, a QR code should be at least 10-20cm wide. For larger posters (A1, A0) viewed from further away, scale up proportionally. Always test scanning from the expected viewing distance before printing in volume.
What size should a QR code be on a billboard?
Billboard QR codes need to be substantially larger because of viewing distance. For a billboard scanned from 10-20 metres, the QR code should be at least 1-2 metres wide. Note that scanning QR codes from a moving vehicle is generally unreliable, so static viewing positions are recommended.
Does adding a logo affect the minimum size?
Yes. Logos cover part of the QR code, reducing readable data. Use higher error correction (H level, 30%) when adding logos, and increase the QR code size by 20-30% to compensate. Keep the logo to under 30% of the code area for reliable scanning.
What resolution should I use for printing QR codes?
Use 300 DPI for professional print quality (business cards, brochures, packaging). For large format printing viewed from distance (banners, billboards), 150 DPI is often sufficient. SVG format scales perfectly to any size and is ideal for print. LinkScan exports SVG free on every plan.
Can I make my QR code smaller with higher error correction?
No. Higher error correction actually adds more data to the QR code, making each module (square) smaller. This can make scanning harder at a distance. Use higher error correction for durability against damage and partial obstruction, not for size reduction.
Related guides
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Last updated 25 May 2026