QReamer
The most common QR code mistake isn't design — it's size. A code that looks fine on screen can be completely unscannable in print because it was sized by eye rather than by the physics of how phone cameras read QR codes. This guide gives you exact numbers for every common print format.
The Core Rule: Minimum 2.5 cm (1 inch) at the Intended Scan Distance
QR codes work because a phone camera can resolve the individual modules (the small squares that make up the pattern) at a given distance. The key variable is the ratio between the QR code size and the scan distance. A rough rule of thumb used by most print designers:
Minimum QR code size = scan distance ÷ 10
So if someone will scan from 25 cm away (holding their phone over a table tent), the minimum safe size is 2.5 cm. If they're scanning a poster on a wall from 1 meter away, the code needs to be at least 10 cm.
This is a floor, not a target. Bigger is always better within the constraints of your design.
Size Guide by Print Format
Business Card (8.5 × 5.4 cm)
- Recommended QR size: 2.2 × 2.2 cm to 2.8 × 2.8 cm
- Typical scan distance: 20–30 cm
- Safe zone: Leave at least 4mm white margin around all four sides of the code
- DPI: Export at 300 DPI minimum; 600 DPI for offset printing
- Notes: Business cards are scanned at close range, so a small code works — but don't go below 2 cm. Avoid placing the code on a dark background; if your card is dark, add a white border pad around the code.
Table Tent / Menu Insert (10 × 15 cm typical)
- Recommended QR size: 4 × 4 cm to 6 × 6 cm
- Typical scan distance: 25–40 cm
- Safe zone: 5mm white margin minimum
- DPI: 300 DPI for digital print; 150 DPI acceptable for laser print
- Notes: Diners scan from a seated position. Test the code in your restaurant lighting before finalizing — low-contrast ambiance lighting can slow scan times, so maximize contrast and size.
Flyer (A5 / A4)
- Recommended QR size: 3.5 × 3.5 cm (A5) · 5 × 5 cm (A4)
- Typical scan distance: 30–50 cm
- Safe zone: 6mm white margin
- DPI: 300 DPI
- Notes: Flyers get picked up and read at arm's length. The code doesn't need to be large, but it does need enough contrast to stand out on a busy layout. Consider a white panel behind the code if the flyer has a colored or photo background.
Poster (A2 / A1 / 24×36 in)
- Recommended QR size: 8 × 8 cm (A2) · 12 × 12 cm (A1) · 10 × 10 cm (24×36 in)
- Typical scan distance: 50–100 cm
- Safe zone: 8–10mm white margin
- DPI: 150 DPI minimum at print size (use SVG output from QReamer to avoid pixelation)
- Notes: At poster scale, always use vector SVG or a very high-resolution PNG. Raster images scaled up from a small download will produce fuzzy module edges that confuse scanners.
Banner (Pull-Up or Wide Format)
- Recommended QR size: 15 × 15 cm to 25 × 25 cm
- Typical scan distance: 1–2 meters
- Safe zone: 15mm white margin
- DPI: 72–100 DPI at final print size (wide format prints at lower DPI by design; again, use SVG)
- Notes: At banner distances, error correction becomes critical. QReamer codes use H-level error correction (30% data restore), which tolerates more damage and degradation.
Billboard / Outdoor Large Format (> 1 meter)
- Recommended QR size: At least 10% of the total billboard width
- Typical scan distance: 3–10 meters
- Safe zone: 20mm+
- Notes: Billboards are genuinely borderline for QR codes. Pedestrians scanning at 3 meters need a massive code. If your billboard is purely vehicle-audience, skip the QR code — no one scans while driving. Foot-traffic billboards at bus stops or transit stations work well.
The Safe Zone (Quiet Zone): Non-Negotiable
Every QR code requires a clear white border — called the quiet zone — around all four sides. Without it, scanners can't detect where the code begins. The minimum quiet zone is 4 modules wide (roughly 10% of the total code size). When in doubt, add more white space rather than less.
What kills the quiet zone:
- Bleeding the code to the edge of a panel
- Dark-colored backgrounds touching the code border
- Drop shadows or glow effects applied directly to the code image
- Overlapping text or decorative elements
DPI and Resolution: Use SVG Output
QReamer exports both PNG (raster) and SVG (vector). For anything larger than a business card, use the SVG:
- SVG scales to any size without loss of sharpness
- No DPI to worry about — the file is mathematically defined
- Your printer's RIP software handles it correctly at any output size
If your printer or design tool requires a raster file, export the SVG at 3× the final print size at 300 DPI, then place it at 33% in your layout tool. This ensures plenty of headroom.
Quick Test Before You Print
Print a proof at final size and scan it with:
- A current iPhone (stock Camera app)
- A current Android (Google Lens or stock camera)
- An older Android at least 3 years old if your audience is broad
If all three scan cleanly under normal room lighting, you're good. If one fails, increase the size by 20% and test again.
Frequently Asked Questions
What is the absolute minimum size for a QR code to be scannable?
Most phone cameras can resolve a QR code as small as 1.5 cm at 15 cm scan distance, but this is unreliable under real-world conditions (slight camera shake, non-ideal lighting, older devices). The practical minimum you should go below for any printed material is 2.5 cm × 2.5 cm.
Does adding a logo to the center of a QR code affect scannability?
Yes, but QR codes are designed for this. The center region is covered by the error correction layer. As long as the logo covers less than 30% of the total code area and you use H-level error correction, the code will still scan reliably. QReamer applies H-level error correction by default on all generated codes.
My QR code looks pixelated when I zoom in. Will it still scan?
Probably not after printing. Pixelated module edges confuse scanner algorithms. Download the SVG from QReamer and regenerate your artwork. Never scale a rasterized QR code up from a small export size.
Should the QR code be black on white, or can I use brand colors?
Black on white is the most reliable. Colored codes work if you maintain high contrast (dark foreground on light background). Light-on-dark QR codes are technically valid but are poorly supported by older scanner apps. If you must use brand colors, test on at least three devices before committing to print.
Does module shape (dots, rounded squares) affect scan reliability?
Slightly, at smaller sizes. Circular dot modules have slightly lower scan success rates on old or budget phones because the module boundaries are softer. At full recommended sizes on modern phones, the difference is negligible. If you're printing at minimum size or for a broad audience with varied devices, use the default square modules.
How do I know if my QR code will print clearly at large format?
Export as SVG from QReamer. SVG is resolution-independent and will reproduce crisply at any output size. If your print vendor requires raster, ask them what PPI they need at the final output size and render the SVG accordingly — or supply the SVG directly if their workflow supports it.