A compact QR variant with a single finder pattern and symbol sizes from 11×11 to 17×17 modules, designed for marking very small parts and labels where a full QR code cannot fit.
Micro QR is a shrunken sibling of the standard QR code, created for applications where even the smallest regular QR symbol is too large: printed circuit boards, electronic components, surgical instruments, small pharmaceutical labels, and tiny asset tags. Where a standard QR code bottoms out at 21×21 modules, Micro QR defines four versions — M1 through M4 — at 11×11, 13×13, 15×15, and 17×17 modules respectively.
One finder pattern instead of three
The most visible difference is structural: Micro QR carries only a single finder pattern in the top-left corner, plus a shortened timing track along two edges. Dropping two finder patterns and the alignment patterns saves precious modules in symbols this small. Orientation is unambiguous with one finder because the symbol's asymmetry is total — there is only one corner with the 1:1:3:1:1 marker. The trade-off is reduced tolerance for rotation and perspective distortion compared with full QR, which is acceptable because Micro QR is typically read by fixed industrial cameras at controlled distances, not by hand-held phones at odd angles.
Capacity and error correction
Capacities are modest, as the sizes suggest. An M4 symbol at Error Correction Level L holds 35 numeric digits (or 21 alphanumeric characters); M1, the tiniest, holds just a handful of digits and offers error detection rather than full correction. Only two error correction levels (L and M) are defined for Micro QR — the higher Q and H levels would consume too much of the tiny data area to be useful. The quiet zone requirement is also relaxed to 2 modules, reflecting the controlled imaging environments where these codes are deployed.
Where Micro QR fits — and where it does not
Micro QR is an industrial format, standardized alongside QR in ISO/IEC 18004. Its natural habitat is direct part marking: laser-etched or dot-peened onto metal, printed on miniature labels, or etched into silicon, then read by machine-vision systems on production lines. It is not a consumer format. Phone camera apps vary wildly in Micro QR support — many will not detect the single-finder symbol at all — so never use Micro QR for anything a customer is expected to scan. If the use case involves human scanning with phones, use a standard QR code and solve the space problem with a short payload, not a smaller symbology.
Choosing between Micro QR and alternatives
For ultra-small marking, the decision tree runs: Micro QR for the smallest machine-readable footprints within the QR ecosystem; Data Matrix for even smaller sizes and the broadest industrial reader support (it is the dominant choice in electronics and aerospace); and standard QR whenever a phone might be the reader. The three symbologies overlap in capability but differ in ecosystem — reader support, not raw specification, usually decides.
Diagram description: Size comparison of Micro QR M1 through M4 beside a standard Version 1 QR code at the same module pitch, highlighting the single finder pattern and the 2-module quiet zone.