QR codes that scan first time: size, contrast and placement
By Online Business Cards Editorial Team | Published | Updated | Sharing your card
Most QR codes that fail are too small, too low-contrast or crammed against other artwork. A few simple rules make your digital business card code scan first time.
A QR code that does not scan is worse than no code at all: it makes people feel the problem is them. The good news is that almost every failure comes down to four things you control — size, contrast, the empty border around the code, and where you put it.
This guide applies to the QR code for your digital business card wherever it appears: on a slide, a stand banner, a shop window, a menu, packaging you already print, or your phone screen.
How big should a QR code be?
A useful rule of thumb is that a QR code can be scanned from roughly ten times its own width. So:
Code width | Comfortable scanning distance | Typical use
2 cm | About 20 cm | Leaflets, labels, packaging
5 cm | About 50 cm | Counter signs, table cards
10 cm | About 1 metre | Posters at eye level
30 cm | About 3 metres | Stand banners, window displays
Treat 2 cm as a practical minimum for anything held in the hand. If people will be standing back — at an exhibition stand, or reading a slide from the middle of a room — go bigger than you think you need, then test it.
Leave a quiet zone
QR codes need an empty margin around them so a phone can tell where the code starts and stops. The QR code standard (ISO/IEC 18004) specifies a quiet zone four "modules" wide — a module being one of the small squares the code is made of. In practice, leave a clear border of at least four of those squares on every side, with no text, lines or images touching the code.
Get the contrast right
- Dark code on a light background. Black or a deep colour on white or a pale background is the most reliable combination.
- Avoid inverted codes. Light codes on dark backgrounds look stylish, but not every scanner reads them.
- Be careful with colour. Brand colours are fine if they are dark enough. Pale blues, yellows and greys often fail.
- Avoid glossy or curved surfaces where reflections or bending distort the pattern.
Logos in the middle
You may have seen QR codes with a logo in the centre. These work because QR codes include error correction: some of the pattern can be damaged or covered and the code still reads. There are four levels, set out in the QR code standard ISO/IEC 18004:2015. According to DENSO WAVE, which invented the QR code, they recover roughly 7%, 15%, 25% and 30% of the code respectively. A small logo relies on that spare capacity, so keep it small, use a higher error-correction level, and always test before you print.
Where to place it
- On slides: put the code on your closing slide, large and on a plain background, and leave it up during questions. Add the link as text underneath for anyone watching remotely.
- On a stand: place it at chest to eye height, not near the floor, and away from where people will stand in front of it.
- On a counter or table: angle it towards the customer and make sure it is well lit.
- On your phone: turn the brightness up and avoid screen protectors with heavy glare.
Next to every code, add a short line of text telling people what they will get: "Scan to save my contact details" works better than a code on its own.
The code does not need to change when your details do
If your QR code opens your profile link, you can edit your profile as often as you like and the code keeps working. That is why it is worth getting the size and placement right once: you will not have to redo it every time your phone number or job title changes.
Test before you rely on it
Before an event, or before anything is printed:
- Scan it with at least one iPhone and one Android phone.
- Scan it from the real distance people will be standing.
- Scan it in the real lighting — a dim venue is not the same as your desk.
- Check the link opens the right profile, not an old or test version.
Read next: Six ways to share a digital business card, and when each one works best and What to put on a digital business card. You can also browse all our guides, or see how an online business card with a QR code works.
Before you order anything with a code on it, read static or dynamic QR code? What to know first.
Frequently asked questions
What is the smallest size a QR code can be?
For codes people hold in their hand, about 2 cm across is a practical minimum. Smaller codes can work, but they become unreliable on older phones or in poor light.
Can I change the colour of my QR code?
Yes, as long as the code stays dark and the background stays light, with strong contrast between them. Test coloured codes on more than one phone before using them widely.
Why does my QR code scan on some phones but not others?
The usual causes are low contrast, too small a size, a missing quiet zone, glare, or a large logo covering too much of the pattern. Fix those first, then test again.
Do I need a new QR code if I update my digital business card?
No. The code points to your profile link, and the link stays the same when you edit your details. Anyone who scans it sees your latest information.
Can I put my logo in the middle of a QR code?
Yes, if the logo is small and the code uses a higher error-correction level. Always test a printed sample on a few different phones before a full print run.