Aspect Ratio

Aspect ratio is the width-to-height proportion. QR codes are defined as square matrices (1:1) per ISO/IEC 18004. Finder pattern detection assumes square geometry - distorted aspect ratios cause recognition failure.

Common distortion occurs when resizing QR code images in design software without locking aspect ratio. Always enable "constrain proportions" when resizing. Exception: rMQR (Rectangular Micro QR Code) is a variant designed for elongated spaces, but requires specialized decoders.