A printed QR code should be at least 0.8 inches (2 cm) square, and the real answer depends on scan distance. Use the 10:1 rule: code width = scan distance ÷ 10. A flyer read from 12 inches needs a 1.2-inch code. A poster read from 1 meter needs 10 cm.
What is the 10:1 rule for QR code size?
The 10:1 rule says a QR code should be one tenth as wide as the distance people scan it from. Phone cameras resolve a code reliably at about ten times its width. Beyond that, the modules blur together and the scan fails.
The math is simple. Measure where the scanner will stand. Divide by ten. That is your minimum code width. A table tent read from 16 inches needs 1.6 inches. A storefront window read from 2 meters needs 20 cm.
Treat the result as a floor, not a target. Printing 20 to 30 percent larger costs nothing and forgives bad lighting, older phones, and people who scan from farther away than you planned. Nobody has ever complained that a QR code scanned too easily.
QR code size chart by use case
These are minimum sizes at typical scan distances. When in doubt, round up.
| Placement | Typical scan distance | Minimum code size |
|---|---|---|
| Business card | 8 in / 20 cm | 0.8 in / 2 cm |
| Flyer or brochure | 12 in / 30 cm | 1.2 in / 3 cm |
| Table tent or menu | 16 in / 40 cm | 1.6 in / 4 cm |
| Poster | 3.3 ft / 1 m | 4 in / 10 cm |
| Window or storefront | 6.5 ft / 2 m | 8 in / 20 cm |
| Trade show banner | 10 ft / 3 m | 12 in / 30 cm |
| Billboard | 50 ft / 15 m | 5 ft / 1.5 m |
How big should a QR code be on a billboard?
Apply the same rule and the numbers get honest fast. A billboard read from 50 feet needs a 5-foot code. Read from 100 feet, it needs 10 feet. On a standard 14-by-48-foot bulletin, a 10-foot code eats most of the design.
There is a second problem. The main audience for a highway billboard is moving at 70 mph. A driver should not be framing your code in a camera, and a passenger has about four seconds to try. Billboard QR codes work for foot traffic, transit riders, and red lights. For everyone else, print a short memorable URL next to the code. The code serves the people who can stop. The URL serves the rest.
Does the amount of data change the size a QR code needs?
Yes. More data means more modules — the small black squares — packed into the same printed area. A code holding 30 characters might use a 25-by-25 grid. A code holding 300 characters uses a much denser grid, so each module prints smaller and the camera needs more size or less distance to resolve it.
The fix is to encode less. A short URL produces a sparse, forgiving code. A 400-character tracking URL produces a dense one that fails at the margins. This is one practical argument for dynamic QR codes: they encode a short link like qranite.com/r/xxx, so the printed code stays sparse no matter where it points.
Error correction matters too. QR codes ship with four levels — L, M, Q, and H — that survive 7, 15, 25, and 30 percent damage respectively. Higher levels add modules, which adds density. Use M for most print work. Use H if you put a logo in the center, because the logo is damage the code must route around.
How much quiet zone does a QR code need?
The quiet zone is the blank margin around the code, and the spec calls for four modules of clear space on every side. In practice: leave a margin of at least one tenth of the code's width, in the same color as the code's background, on all four sides.
Scanners use the quiet zone to find the code's edges. Print the code against a busy photo, a dark background, or tight against a border, and scans fail even when the size is right. Plain background, dark code, real margin. The Qranite generator bakes a correct quiet zone into every download, so the main risk is a designer cropping it off later. Ask them not to.
What resolution do I need for printing a QR code?
Use SVG whenever your printer or designer accepts it. SVG is vector, so it stays perfectly sharp at any size — business card or banner, same file. Qranite exports SVG free, no signup.
If you need a raster file, aim for 300 DPI at the final print size. Multiply print inches by 300 to get the pixels required. A 4-inch poster code needs 1200 px. Qranite's free PNG export goes to 4096 px, which covers prints up to 13.6 inches at 300 DPI — larger than almost any non-billboard use.
Never upscale a small PNG. Stretching a 200 px code to poster size produces soft, gray module edges, and soft edges are one of the most common reasons a printed code stops scanning. Export at final size or use SVG.
Can a QR code be too big?
Rarely, but yes. A phone has to fit the entire code plus its quiet zone in the camera frame. A 3-foot code scanned from 2 feet away will not fit, and the scan fails. The 10:1 rule has an upper bound of roughly 5:1 — closer than half the rule's distance, and framing gets awkward.
This only bites at extremes: giant wall graphics in narrow hallways, floor decals people stand on. For everything in the chart above, bigger is still the safe direction. Print the size the distance demands, add 20 percent, test one scan from the real distance before the full print run. That last step catches almost everything.