Practical guide
QR codes and barcodes: choosing a format and printing safely
A code image represents data; it does not register a product or protect information. Choose a format accepted by the phone, retailer or your own system and test a scan before sharing.
QR: static content without an intermediary
QR can hold a complete https:// address, plain text, Wi-Fi configuration, a phone number or contact card. Static codes store content directly. We add no intermediary redirect address or our own scan tracking.
The code does not expire because of the generator, but its content can become outdated. Changing a Wi-Fi password requires a new image; a printed link still points to the same address. The destination website may run its own analytics when opened.
Source: ZXing — URL, phone, Wi-Fi and vCard content formats.
Wi-Fi passwords and contact data are readable
Anyone scanning a QR can read its content, including a network password. Encoding and error correction are not encryption. For guests, use an appropriately restricted network instead of publishing access to a private network.
Inputs remain in browser memory. Files, prints and copied content are separate copies under your control. Share only contact data intended for publication and test importing the card on the intended phone.
Source: ZXing — URL, phone, Wi-Fi and vCard content formats.
EAN-13 does not allocate a GTIN
EAN-13 represents 13 digits. For a 12-digit body, the check digit uses alternating weights 1 and 3 from the left and (10 − sum modulo 10) modulo 10. An incorrect final digit in a 13-digit input is rejected, and leading zeroes remain in the number.
A valid checksum does not establish GTIN allocation or a right to use the number. Example 5901234123457 illustrates the calculation and is not a number assigned to your product. For trade in Poland, establish the number through GS1 Polska or the relevant organisation and check retailer requirements.
Source: GS1 — GTIN-13 check-digit calculation; GS1 — product numbering, quiet zones and print quality.
Code 128 for systems that accept it
Code 128 can hold an internal number or short ASCII text such as MAG-001. The tool preserves letter case and spaces and caps content at 80 characters. Polish accented letters and control characters are rejected.
Ordinary Code 128 is not GS1-128. This generator does not add FNC1 or application identifiers for dates, batches or other GS1 fields. Do not assume a retailer or warehouse accepts the code without checking its system specification.
Margins, contrast and scan testing
A four-module margin surrounds each QR code. Barcode images also contain white zones at the sides. Do not crop them, place text over them or stretch the barcode image unevenly. Black bars on white provide clear contrast.
SVG is vector-based; PNG has a fixed pixel count. Neither format by itself establishes the correct physical dimensions, print quality or label compliance with GS1 requirements. Test a scan on the intended material, at final size and using recipient equipment.
Source: DENSO WAVE — four-module QR quiet zone; GS1 — product numbering, quiet zones and print quality.
Frequently asked questions
Does error correction encrypt the QR?
No. It helps read a damaged symbol but does not conceal its content. A Wi-Fi password remains readable to anyone scanning.
Does a valid EAN mean a registered product?
No. We check the check digit and draw a symbol without accessing product registers or allocating GTINs.
Sources and scope
This is technical guidance, not code or print-quality certification. Product numbers must be used according to the relevant GS1 organisation and recipient requirements.
Tools covered by this guide
QR code generator
Create static QR codes for links, text, Wi-Fi, phone numbers and contact cards. Download SVG or PNG.
Barcode generator
Create EAN-13 or Code 128 barcodes. Check the check digit and download a black-and-white SVG or PNG.