How Big Should a QR Code Be? The Complete Print Size Guide
A QR code that doesn't scan is worse than no QR code at all. Sizing errors are the #1 reason printed QR codes fail in the real world. Here's the exact size to use for every placement — from business cards to highway billboards — plus the mathematical formula behind it.
The 10:1 Scan Distance Rule
The golden rule of QR code sizing is based on optics and camera lens physics. It is extremely simple:
QR code width ≥ Scan distance ÷ 10
If a customer is standing 1 metre (100 cm) away, the QR code must be at least 10 cm wide.
This ratio works because smartphone camera lenses need the QR code to fill a sufficient percentage of the camera frame to trigger the decoding software. If the code is too far away relative to its physical size, the camera cannot mathematically resolve the individual black and white squares (called modules).
QR Code Size Chart by Use Case
| Placement | Typical Scan Distance | Minimum QR Size |
|---|---|---|
| Business card | 10–20 cm | 2 × 2 cm (0.8 inches) |
| Product packaging | 15–30 cm | 2.5 × 2.5 cm (1 inch) |
| Restaurant table card | 30–50 cm | 4 × 4 cm (1.5 inches) |
| Counter standee | 50–80 cm | 8 × 8 cm (3 inches) |
| Wall poster (A4/A3) | 1–1.5 m | 10–15 cm (4-6 inches) |
| Shop window | 1–2 m | 15–20 cm (6-8 inches) |
| Banner / hoarding | 3–5 m | 30–50 cm (1-1.5 feet) |
| Billboard | 10–20 m | 1–2 m (3-6 feet) |
| Projector slide | 2–5 m (audience) | Fill ⅓ of the slide height |
3 Other Factors That Affect Scannability
Size isn't the only metric. Even a perfectly sized code will fail if you ignore these three optical requirements:
- Data Density: Longer URLs create more data modules, making the grid denser. A 30-character URL creates a simple, blocky code that scans fine at 2 cm. A 200-character URL creates a dense maze of tiny dots that will blur together at 2 cm. Rule: Shorten long URLs using bit.ly before generating if you must print small.
- The Quiet Zone: You must leave a white margin around the entire QR code at least 4 modules wide. This is how the camera identifies where the code begins and ends against the background design.
- High Contrast: Always use a dark code on a pure light background. Light-on-dark (inverted) QR codes fail to scan on a significant percentage of Android camera apps.
Why SVG Beats PNG for Print
A PNG file is a raster image—a fixed grid of pixels. If you enlarge a small PNG for a large banner, the edges of the squares will blur. Blurry module edges are the #1 cause of failed scans on large-format prints because the camera cannot find the sharp contrast lines it relies on.
An SVG is a vector format: it describes the QR code using mathematical geometry. This means you can scale an SVG from the size of a postage stamp to the size of a skyscraper, and the edges will remain perfectly, mathematically sharp.
QRcraft's free QR code generator offers professional SVG vector downloads entirely for free.
The Pre-Print Checklist
- Print a test copy on regular paper at the exact physical size you intend to use.
- Tape it to the wall and step back to the actual distance your customer will be standing.
- Scan it with both an iPhone and an older Android device.
- Test in the actual lighting conditions (a brightly lit office is not a dim restaurant).
- Verify the link opens the correct page.
Frequently Asked Questions (FAQ)
What is the absolute minimum size for a printed QR code?↓
How do I calculate QR code size for a poster or banner?↓
Should I use PNG or SVG for printing QR codes?↓
Why does my small QR code fail to scan even though it's 2cm wide?↓
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