A QR code (Quick Response code) is a two-dimensional barcode that stores information in a matrix of black and white squares. When scanned by a smartphone camera or QR scanner, the pattern is decoded back into the original data—whether it's text, a URL, contact information, or WiFi credentials. QR codes use Reed-Solomon error correction, allowing them to be read even if partially damaged or obscured.

QR codes offer four error correction levels: L (Low) recovers ~7% of data, ideal for clean environments; M (Medium) recovers ~15%, suitable for general use; Q (Quartile) recovers ~25%, good for slightly dirty or damaged conditions; H (High) recovers ~30%, best for logos or harsh environments. Higher correction levels produce denser QR codes with less data capacity.

The storage capacity depends on the data type and error correction level. For alphanumeric text at Low (L) correction, QR codes can store up to 4,296 characters. For binary data, the limit is around 2,953 bytes. With High (H) error correction, alphanumeric capacity drops to about 1,800 characters. For best scanning reliability, keep content concise and use Medium (M) correction.

QR codes themselves are just data containers—they're neither inherently secure nor dangerous. However, always verify the destination before scanning unknown QR codes, as malicious actors can encode phishing URLs or trigger unwanted actions. When generating QR codes, the data is processed entirely in your browser; no information is sent to any server, ensuring your privacy.

For reliable scanning, a printed QR code should be at least 2 x 2 cm (0.8 x 0.8 inches). The ideal size depends on the scanning distance—a good rule of thumb is a 10:1 ratio (distance to QR code size). For example, if users scan from 30 cm away, the QR code should be at least 3 cm wide. Always include a quiet zone (white margin) of at least 4 modules around the QR code.

Yes! You can customize both the foreground and background colors. However, ensure high contrast between the two—dark foreground on light background works best. Avoid light-on-dark combinations that confuse scanners. The foreground should always be significantly darker than the background. Our tool lets you preview the contrast in real-time before downloading.