How do I read a barcode?

How it works

A QR code or barcode is only text written in black and white squares or bars. The scanner reads that text on your device, from the camera image or the picture you choose, and nothing is sent anywhere. Then it tells you what kind of text it is: a web address, Wi-Fi login, contact card, bank transfer, product number or plain text.

Links get the most attention, because a code on a parking meter or a poster can be a sticker placed by a scammer. The scanner never opens a link by itself. It shows the real site name, decodes international names (xn--80ak6aa92e.com shows as аррӏе.com: it looks like apple.com, but every letter is Cyrillic), and flags short links, hidden names before the address (https://mybank.com@other.net goes to other.net) and addresses that run code instead of opening a page.

Barcodes on products carry a GS1 check digit: multiply the digits alternately by 3 and 1 from the right, and the last digit brings the sum up to the next multiple of ten. For 400638133393, the sum is 89, so the check digit is 1 and the full EAN-13 is 4006381333931. A wrong check digit means a misread or a made-up number. Payment codes follow the EPC QR standard and the Finnish bank barcode guide.

No warning signs doesn't prove a link or payment is safe: it only means nothing looks unusual in the text itself. A short link isn't followed, so its destination stays unknown. Check payment details in your banking app before you pay.