QR Code Size and Quiet Zone: How Big Should a QR Code Be?
By ScanHatch · Published · 4 min read
Most QR codes that fail in the real world don't fail because of their content. They fail because they're printed too small for the distance, or because a design eats into the blank margin around them. Both are easy to get right with a few numbers.
Size depends on scanning distance
A widely used rule of thumb is a 10:1 ratio: the code's width should be at least a tenth of the distance it's scanned from. It's a starting point, not a guarantee, because camera quality, lighting and the code's density all move the number.
| Where it's scanned from | Distance | Minimum width |
|---|---|---|
| Business card, product label in the hand | 20–30 cm | 2–3 cm |
| Table card, menu, flyer | 30–50 cm | 3–5 cm |
| Poster on a wall | 1–2 m | 10–20 cm |
| Window sign seen from the pavement | 2–3 m | 20–30 cm |
| Billboard or banner | 5 m and more | 50 cm and more |
About 2 × 2 cm is a sensible minimum even for close scanning. Smaller codes can work but leave little margin for older phones.
Density matters as much as size
What a camera actually needs to resolve is each module, the individual square. The more data in a code, the more modules it has, so the smaller each one is at a given printed width.
Example
A short link makes a 25 × 25 grid. Printed 2 cm wide, each module is 0.8 mm. A long tracking link needs 57 × 57 modules at error-correction level H, so at the same 2 cm each module shrinks to about 0.35 mm, which is much harder for a phone to resolve. That code needs printing about twice as wide.
If you can't make a code bigger, make it simpler: shorten the link, remove unnecessary tracking parameters, or use a lower error-correction level when there's no logo.
The quiet zone
The quiet zone is the blank margin around a QR code. The QR code standard (ISO/IEC 18004) specifies 4 modules on every side. Scanners use it to tell where the code ends and the surrounding design begins; text, borders or busy backgrounds right up against the code can make the finder patterns hard to pick out.
- The margin needs to be as light as the code's background, not just empty. A code placed on a patterned background still needs its own light border.
- Many phones cope with 2 modules, but 4 is what the standard asks for and costs little.
- Don't trim the margin off a downloaded image to save space. It's part of the code.
- Micro QR, a smaller variant, needs only 2 modules.
The QR Code Generator adds a 4-module quiet zone by default, and the QR Validator measures the clear margin in an uploaded image, including margins spoiled by nearby content.
Exporting files that print sharply
- Use SVG or PDF for print. They're vector formats, so the module edges stay crisp at any size.
- If you must use PNG, work out the pixels you need: at 300 dpi, a 3 cm code needs about 354 pixels, and a 10 cm poster code about 1,181.
- Never stretch a code unevenly. Squashed modules confuse scanners.
- Leave the code square in design software, and scale it with the aspect ratio locked.
QR codes on screens
On a screen, the equivalent of print size is the displayed size. Codes in presentations and on TV need to be large enough for people at the back of the room; codes on phones for tickets should be displayed at full brightness. Screens show fine detail well, so a lower error-correction level is usually fine.
Frequently asked questions
What is the smallest QR code that will scan?
Around 2 × 2 cm is a practical minimum for close scanning with a phone. Smaller codes can work with short content and good printing, but test them.
Can a QR code be too big?
Rarely. It just needs to fit entirely in the camera's view from where people stand.
Does the quiet zone have to be white?
It must be as light as the code's background and free of other marks. White is simplest.