QR code size calculator
The distance people scan from decides the smallest a code can be printed. This does the arithmetic, including the allowance a logo needs.
How big should a QR code be for a poster?
A QR code on a poster should be at least 3.6 inches (9 cm) wide if people scan it from 3 feet away. The rule is a 10:1 ratio: divide the scanning distance by ten to get the minimum code width. A billboard read from 30 feet needs a 3-foot code. Add 20% for a code carrying a logo.
Why the 10:1 ratio works
A camera has to resolve individual modules — the small squares that make up the pattern. Phone sensors and autofocus vary, but at roughly a tenth of the viewing distance a code presents each module at enough pixels for reliable decoding, with margin for motion, angle and imperfect light. The ratio is a floor, not a target: printing larger is nearly always cheaper than a reprint.
Minimum QR code size by print type
| Print type | Typical scanning distance | Minimum width |
|---|---|---|
| Business card | 6 in / 15 cm | 0.6 in / 1.5 cm |
| Restaurant menu or table tent | 12 in / 30 cm | 1.2 in / 3 cm |
| Product packaging | 12–18 in / 30–45 cm | 1.2–1.8 in / 3–4.5 cm |
| Flyer or A4 poster | 3 ft / 1 m | 3.6 in / 9 cm |
| Retail window | 6 ft / 2 m | 7.2 in / 18 cm |
| Trade-show banner | 10 ft / 3 m | 12 in / 30 cm |
| Billboard | 30 ft / 9 m | 36 in / 90 cm |
Every row is the ratio, nothing else — which is why the table and the calculator above never disagree. One floor the ratio does not know about: below roughly 0.8 in / 2 cm, ink spread on uncoated stock starts merging modules whatever the arithmetic says, so treat that as the practical minimum for anything printed on paper.
What breaks scanning at small sizes
- Ink spread. On uncoated stock, ink bleeds into the white modules and merges them. Print small codes at higher error correction.
- A long URL. More data means more modules in the same width, so each module gets smaller. A short link keeps the pattern coarse — this is a real reason to encode a short link rather than the destination.
- Cropped quiet zone. Designers trim the white margin to make a code fit. Scanners then cannot locate the pattern at all.
- Low contrast. A brand-coloured code on a brand-coloured background can look fine on screen and fail in a dim restaurant.
If a code is already printed and failing, work through the troubleshooting guide.
Questions
The things people ask before they commit something to paper.
Can a QR code be too big?
Rarely, but yes. Phone cameras need the whole code inside the frame, so a code larger than about a third of the viewing area forces people to step back. On a billboard that is fine; on a table tent it means the code cannot be scanned from arm’s length.
Does the quiet zone count towards the size?
Yes. The quiet zone is the blank margin around the pattern, four modules wide, and scanners use it to find the code. Measure your printed code including that margin. Cropping it to save space is the most common cause of a code that will not scan.
Do I need a bigger code if it has a logo?
Add about 20%. A logo covers data modules, so the code has to be printed at error-correction level H and read more of the remaining pattern. More size gives the scanner more pixels per module, which is what buys back the reliability the logo costs.
What size QR code works on a business card?
The ratio gives 0.6 inches for a card read at six inches, but print it at 0.8 inches or 2 cm. That is the practical floor for consumer printing: below roughly 0.6 inches, ink spread on uncoated card starts merging modules and scan rates fall sharply.