How Micro QR differs from a regular QR code
A Micro QR code uses one finder pattern in a corner instead of the three that a regular QR code has. Dropping two finder patterns frees up space, so a very short message fits in a much smaller symbol. The timing patterns run along the top and left edges rather than between the finder patterns.
Micro QR also needs only a 2-module quiet zone, half of the 4 modules a regular QR code asks for. Together these changes make it useful where the printable area is only a few millimeters wide, such as on electronic components or small medical items.
Sizes and capacity
Micro QR has four versions, each two modules larger per side than the one before. Capacity is small by design, and the smallest version supports only error detection, not error correction.
- M1: 11×11 modules, up to 5 numeric digits, error detection only
- M2: 13×13 modules, error correction levels L and M
- M3: 15×15 modules, error correction levels L and M
- M4: 17×17 modules, levels L, M and Q, up to 35 numeric digits or 21 alphanumeric characters at level L
- No version supports level H
Where it is defined and read
Micro QR is specified in ISO/IEC 18004, the same standard that defines the QR code. It was developed by DENSO WAVE, which created the original QR code.
Support is the main limitation. Industrial scanners and many barcode SDKs read Micro QR, but many built-in phone camera apps do not, so it is a poor choice for codes meant for the general public.