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GlossarySharing and scanning

How Does QR Code Scanning Work?

QR code scanning is the act of pointing a phone camera at a QR code so the phone reads the pattern and acts on what it holds, usually by offering to open a web address. Modern iPhones and Android phones do this in the built-in camera app, with no separate scanner required.

What the Phone Does

The camera finds the three corner markers, works out the orientation and angle, and reads the grid of modules into text. It then checks the error correction to repair any misread squares, and decides what the text is. A web address produces a prompt to open it; a contact produces a prompt to save it. The person never has to press a shutter or open anything special beyond the camera app.

Why Scans Fail

Almost every failure traces to one of a few causes: too little contrast, no quiet zone around the code, a code printed too small for the distance, a glossy surface that reflects light back at the camera, or a pattern so dense that a casual scan cannot resolve it. Shortening what the code encodes fixes the last one at the source, and a quick test on the real printed card, in the real lighting, catches the rest before a full run is ordered.

Counting Scans

A scan can only be counted if it passes through something that can count it. A code that links straight to a page tells nobody anything, whereas a dynamic code goes through a redirect, and each pass can be recorded. VCardForever keeps a count of scans and of views for each card, so you can see whether a code is actually being used and compare one placement against another, such as a flyer against a badge.

A Note on Safety

People are right to be wary of scanning unknown codes, since a code can send a phone to any address. Phones show the address before opening it, and a polite card makes it obvious what scanning will do, with a few words printed beside the code such as Save my contact. That small line does more for scan rates than any design touch.

Frequently asked questions

Why won’t my QR code scan?

Check contrast, the blank margin around the code, its printed size and any glare. A code that carries a short link is much more forgiving than one packed with data.

Do I need a QR scanner app?

No. The camera app on current iPhones and Android phones reads QR codes directly.

Can I see how many times my card was scanned?

Yes. Each card keeps scan and view counts, so you can see whether a printed code is being used.

Keep reading

Related terms

QR CodeA QR code (Quick Response code) is a two-dimensional barcode, a square grid of dark and light modules, that stores text such as a web address and can be read by a phone camera. Unlike a traditional barcode it holds data in both directions and still scans when partly damaged or obscured.Dynamic QR CodeA dynamic QR code encodes a short, fixed redirect link rather than the destination itself, so the destination can be changed at any time without altering or reprinting the code. Because the printed pattern never changes, a dynamic code can be edited after printing and can count its scans.QR Code Business CardA QR code business card is a business card whose contact details are reached by scanning a printed QR code. The code can either encode the details directly, which fixes them permanently, or point at a contact page, which keeps them editable after printing.Static QR CodeA static QR code encodes its destination or data directly in the pattern, so the code can never be edited and no service is needed for it to work. Whatever was encoded on the day it was generated is what every scan returns, for as long as the code remains legible.

Put this into practice with your own card

Put your details on one card page, share it by link or QR code, and change them whenever they change. The printed code keeps working. No credit card required to start.

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