Summary: Practical sizing guidance based on scanning distance, plus quiet zone, contrast, resolution, and a testing routine that catches problems before you print.
Q: What is the smallest a QR code can be?
A: As a rough starting point, keep a printed code at least about 2 x 2 cm (0.8 inch) for close scans, then confirm with a real test. Denser codes with more data or a logo need to be larger. Always verify at the actual print size rather than relying on a fixed number.
Q: What is the 10-to-1 rule for QR codes?
A: A widely used guideline: the minimum code width should be about one tenth of the scanning distance. To be read from 2 metres away, aim for a code around 20 cm wide. Treat it as a starting estimate and test in the real setting.
Q: Does adding a logo require a bigger code?
A: Usually yes. A logo covers modules, so you should raise the error-correction level and often increase the size to keep the scan reliable. Test any code with a logo on more than one phone.
Q: What resolution should I export for print?
A: Print at 300 DPI or higher, or use a vector export where available, so edges stay crisp at the final size. Never scale up a small raster image, since that produces blurry modules that fail to scan.
Q: Does a longer URL produce a larger QR code?
A: Yes. More data means more modules, which means a denser pattern. A very long URL can produce a code that needs to be printed larger to remain scannable. Shortening the URL (using a URL shortener or a cleaner page path) reduces density and improves reliability.
Q: Can I print a QR code on a curved surface like a mug or bottle?
A: Yes, but curves distort the pattern. Use a higher error-correction level (Q or H), keep the code smaller relative to the curve, and test scanning from multiple angles. Some curvatures are too severe for reliable scanning.
The most common reason a QR code fails is simple: it was printed too small for the distance it needs to be scanned from, or the surrounding factors, like contrast and whitespace, were neglected. This guide gives you reliable sizing for both print and screens, including specific recommendations by industry, DPI and resolution guidance, and a real-world testing checklist, without making promises that ignore your specific setting.
The scanning-distance rule
The most useful rule of thumb is the 10-to-1 ratio: the code should be about one tenth as wide as the maximum distance it will be scanned from. So:
- Scanned from 30 cm (a table or flyer): aim for around 3 cm wide.
- Scanned from 1 m (a counter display or window): aim for around 10 cm wide.
- Scanned from 2 m (a poster): aim for around 20 cm wide.
- Scanned from 5 m (a wall or window display): aim for around 50 cm wide.
- Scanned from 10 m (a large banner or billboard): aim for around 100 cm wide.
This is a starting estimate, not a guarantee. Denser codes (those encoding more data or using higher error correction) and lower-end cameras need more size, so round up when in doubt. Lighting conditions, glare, and print quality all affect the practical threshold.
The minimum recommended printed size is 2 cm × 2 cm even for the closest scans. Below that, small print variations and camera focus limitations start to cause consistent failures on budget smartphones.
Practical print sizes
| Placement | Typical scanning distance | Suggested minimum size |
|---|---|---|
| Business card | 15 to 30 cm | 2 to 2.5 cm |
| Table tent / table sticker | 30 to 50 cm | 3 to 4 cm |
| Flyer / brochure | 30 cm | 2.5 to 3 cm |
| Product packaging (small) | 20 to 30 cm | 2 to 2.5 cm |
| Product packaging (large) | 30 to 50 cm | 3 to 4 cm |
| A5 / A4 poster | 30 to 60 cm | 3 to 5 cm |
| A3 / A2 poster | 1 to 2 m | 10 to 20 cm |
| A1 / A0 poster | 2 to 3 m | 20 to 30 cm |
| Retail window display | 1 to 3 m | 15 to 30 cm |
| Billboard / large banner | 5 m and above | 50 cm and above |
Sizing by industry
Different industries have different typical scan distances and placement conditions. Here are targeted recommendations for the most common use cases.
Restaurants and cafés
Table codes are scanned from roughly 30 to 50 cm, so a code between 3 and 4 cm is a solid starting point. The real-world factor is restaurant lighting: dim atmospheric lighting can reduce camera performance significantly. If your venue is intentionally dark, print slightly larger (4 to 5 cm) and test in the actual space. Codes on menus at the front door should be sized for a standing scan distance of about 50 to 80 cm, so aim for 5 to 8 cm.
For the full restaurant guide, see QR codes for restaurants and the step-by-step menu QR code guide.
Real estate
Codes on for-sale signs and window displays are typically scanned from 1 to 3 metres by passers-by. Use the 10-to-1 rule and aim for 15 to 30 cm wide. Outdoor signs also face direct sunlight and weather, which affect contrast and durability. Use high-contrast black on white and laminate the surface. See QR codes for real estate.
Events
Event codes appear in many contexts: on badges (scanned from 20 to 30 cm), on stage screens (scanned from 5 to 20 m), and on printed programmes (30 cm). Size each placement appropriately rather than using one code size for all. A code on a conference screen needs to be very large, often full-screen for a moment. Badge codes should be at least 2.5 cm. Read more at QR codes for events.
Business cards
Business card codes are scanned close up (15 to 25 cm) so a code of 2 to 2.5 cm fits well even on a standard 85 × 55 mm card. Keep the quiet zone clear and avoid placing text right up to the code edge. A vCard code with a full name, phone, email, and website will be denser than a plain URL code; if the pattern looks very dense in preview, trim the content or increase the size to 2.5 cm. See QR codes for business cards.
Product packaging
Packaging codes are scanned at arm’s length (20 to 40 cm) in store lighting conditions. A 2 to 3 cm code is usually sufficient, but curved or non-flat packaging (tins, bottles, tubes) distorts the pattern. Use error-correction level H for curved surfaces and test by scanning the physical product. Read the full guide to QR codes for product packaging.
Quiet zone (whitespace)
The quiet zone is the empty margin around the code. Scanners need it to tell where the pattern begins and ends. The QR standard specifies a clear border at least four modules wide (a module is one of the small squares in the grid). In physical terms, for a 3 cm code this means roughly 1 to 2 mm of clear space on each side.
In practice, be generous. Leave a visible white frame and never let text, borders, brand graphics, or photo backgrounds crowd the edges. Even a partially obscured quiet zone causes failures on some scanners, because the decoder cannot reliably locate the finder patterns.
Contrast and color
Scanners read the difference between dark and light modules, so contrast is critical:
- Use a dark foreground on a light background. Classic black on white is the most reliable.
- Keep the foreground darker than the background, never the reverse.
- Avoid low-contrast pairs such as light grey on white, navy on black, or dark green on dark blue.
- If you tint the code to match a brand color, keep the dark modules genuinely dark (at least a 3:1 contrast ratio, ideally higher).
- Do not place a QR code on a busy photographic background without a white container box behind it.
Logos and complexity
A centered logo looks professional but covers modules. To keep the scan reliable:
- Use error-correction level H, which tolerates up to 30% module loss.
- Keep the logo area under 20 to 25 percent of the total code area.
- Use a simple logo mark rather than a complex full-color wordmark; the busier the logo, the more the underlying modules are obscured.
- Increase the overall code size by 10 to 15 percent compared to the equivalent code without a logo.
- Test the finished code on at least three phones, including an older Android device.
Resolution, DPI, and file format
For print, resolution determines whether module edges are sharp or blurry. Blurry edges merge adjacent modules and destroy the read.
DPI guidance
- 300 DPI minimum for standard print (flyers, cards, brochures).
- 600 DPI for high-quality or small-size print (business cards, product labels).
- Vector (SVG or PDF) for large-format print (posters, banners, billboards). A vector image is resolution-independent and stays sharp at any size.
File format advice
- PNG is the best raster format. It is lossless, so no JPEG compression artifacts soften the module edges.
- JPEG / JPG introduces compression artifacts even at high quality. Avoid for QR codes if at all possible.
- SVG or PDF for large-format print. Infinitely scalable without quality loss.
Never enlarge a small PNG to fill a large poster. Scaling up a raster image blurs the module boundaries. Always generate the code at, or above, the final printed size. If you need a poster-size code, use the largest export resolution available or request a vector format.
Sizing for screens
On screen, the concern shifts from DPI to pixels and viewing distance. A code shown on a slide or shop screen should be large enough that a phone a few metres away can capture it clearly, following the same 10-to-1 idea.
- For a code displayed on a phone screen for someone to scan nearby: at least 240 × 240 pixels at screen resolution.
- For a code on a laptop or desktop screen at about 1 to 2 m: at least 400 × 400 pixels.
- For a code projected on a presentation screen at 3 to 5 m: at least half the slide width, which on a standard 1920 × 1080 presentation is around 400 to 500 pixels in the slide layout.
- For a full-room screen or digital signage at 5 to 10 m: as large as feasible, often full-screen for the moment the code appears.
Avoid displaying codes on reflective or dim screens where glare defeats the camera. Matte screens and good ambient lighting improve scan rates significantly.
How to test before printing
Skipping the test is the most expensive mistake in QR code deployment. A failed code on 5,000 printed menus means a reprint. Here is a reliable pre-print checklist:
- Export or print the code at the exact final size, not a preview on screen.
- Scan it with at least two different phones: ideally one current iPhone and one mid-range Android.
- Test in the real lighting of the location, including any glare, shadows, or lamp flicker.
- Scan from the closest and the farthest realistic distance.
- Confirm the destination opens correctly, not just that the code is detected.
- Check the destination is mobile-friendly: loads quickly, text is readable, no pinch-zoom required.
- If the code is outdoors, check it also in direct sunlight and in overcast conditions.
Only after a code passes every check should you commit to a large print run. For a deeper fault-finding list when something goes wrong, see why a QR code is not working.
Common mistakes
- Sizing for the design, not the distance. A tiny code on a big poster will not scan from across a room.
- Removing the quiet zone to fit a layout. Keep the margin clear; shrink the design element instead.
- Upscaling a low-resolution image. Generate at the final size, or use a vector format.
- Saving as JPEG. Compression artifacts blur module edges. Use PNG or SVG.
- Skipping the real-world test. A screen preview is not proof it will scan in print and real lighting.
- Placing a code on a busy background without a white box. Contrast is as important as size.
- Using a very long URL without shortening it first. More data means a denser pattern; shorter URLs produce simpler, more scannable codes.
Frequently asked questions
Related reading: what is a QR code, static vs dynamic codes, why a QR code is not working, and our URL QR code generator.
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