How big should a QR code be on a billboard?

How does the calculator work?

It applies the 10:1 rule. A phone camera can reliably read a QR code from about ten times the code's width, so the minimum width is the viewing distance divided by 10. The tool converts feet to metres first, then shows the result in centimetres and inches.

The second figure adds the quiet zone: the blank margin of 4 modules (the small squares) on every side of the code. For a short link, the code is 25 modules across, so the quiet zone adds 8 modules and the printed area becomes 33 ÷ 25 of the minimum, about 32% larger. The calculator rounds it up to the next whole centimetre.

What is the formula?

minimum width = viewing distance ÷ 10

print area = minimum width × 33 ÷ 25

Say a poster sits on a platform wall and people read it from the edge of the platform, 3 metres away. The code needs to be at least 30 cm wide, and you should leave space for about 40 cm once the quiet zone is included.

QR code size by viewing distance

Does the length of the URL change the size?

Yes. Every extra character adds modules, so a long URL with UTM tags produces a denser code. At the same printed width each module is smaller and harder to read from a distance. The calculator assumes a short link of around 25 modules, which is what a dynamic code gives you. If you encode a long URL directly, make the code bigger or shorten the link first. You can check how dense your finished code is with the QR code tester.

Which distance should I measure?

Measure from where people stand when they will actually scan, not from the furthest point the ad is visible. For a roadside billboard that is usually the pavement opposite or a queue of traffic. For a bus shelter, it is the bench or the kerb. If the answer is "from a moving car", a QR code is the wrong call to action: use a short web address instead.

What else affects whether a large code scans?

• Contrast: dark modules on a light background. Avoid light-on-dark and busy photos behind the code.
• Light: backlit panels and night-time glare wash out codes. Test the proof under the lighting it will hang in.
• Angle and height: codes placed high above eye level are read at a slant, which shortens the effective distance.

The full walkthrough, with placement tips per format, is in the billboard QR code size guide.

How do I know if the billboard is getting scans?

Give each billboard its own dynamic QR code. BetterQR counts the scans on every code, so you can compare sites, and lets you change the destination after printing. Dynamic codes come with the paid plans; see pricing for the limits.