Micro QR & rMQR

Micro QR and rMQR are the two QR variants for situations where a standard QR won't fit. Micro QR is a square with a single finder pattern (versus three on a standard QR); rMQR is rectangular for narrow labels. Both are in the QR family but scanner support is specialist-only — most phone cameras won't decode either natively.

Micro QR spec: ISO/IEC 18004:2024 Annex M — originally introduced in the 2006 edition.
rMQR spec: ISO/IEC 23941:2022 (Rectangular Micro QR).
Both maintained by: DENSO WAVE (the original QR inventor) via the ISO JTC1/SC31 working group.

Micro QR

Four versions (M1, M2, M3, M4). One finder pattern in the top-left corner instead of three on a standard QR. Payload capacity is much smaller than standard QR.

Version	Size (modules)	Max numeric	Max alphanumeric	Max binary (bytes)
M1	11 × 11	5 digits	—	—
M2	13 × 13	10 digits	6 chars	—
M3	15 × 15	23 digits	14 chars	9
M4	17 × 17	35 digits	21 chars	15

Versions M1 and M2 have no error correction. M3 and M4 support low (L) and medium (M) ECC only. High (H) ECC is not available in Micro QR.

rMQR (Rectangular Micro QR)

Introduced 2022. 32 size variants indexed by row count (7, 9, 11, 13, 15, 17) × column count (27, 43, 59, 77, 99, 139). Designed for narrow label strips — think pharma serialisation, electronic component marking, PCB assembly.

rMQR size	Use case	Approx capacity (binary)
R7×43 (smallest)	Narrow cable label	~7 bytes
R11×77	Pharma vial serialisation	~40 bytes
R17×139 (largest)	PCB / narrow-strip industrial	~361 bytes

Canonical test vectors

Case	Inputs	Output symbology
Micro QR, short numeric	`data=12345`	M1 (11×11)
Micro QR, mixed alphanumeric	`data=PART-X42`	M3 (15×15)
Micro QR, URL (too long → rejected)	`data=https://example.com/very/long/url`	Not encodable — falls back to standard QR.
rMQR, lot serial	`data=LOT12345/BATCH2026`	R11×77 (approx)
rMQR, binary product code	`data=0x7F8A3B... (361 bytes)`	R17×139 (max)

Common pitfalls

Assuming phone-camera support. iPhone Camera decodes standard QR, not Micro QR or rMQR. Android Camera is the same. If your workflow requires a phone scan, use a standard QR at the smallest version that fits your payload (V1 21×21, V2 25×25, etc.) instead.
Over-ambitious payload. Micro QR M1 holds 5 numeric digits. That's not a lot. Strings that obviously won't fit (URLs, vCards) need a larger variant or a standard QR. Every Micro QR generator should fail-loudly when the payload exceeds M4 capacity, not silently upgrade to standard QR.
Module pitch requirement. Industrial scanners need at least 0.2mm module pitch for reliable Micro QR reads (phone cameras need 0.3mm). On a 4mm × 4mm Micro QR M1, the module pitch is ~0.36mm — fine. On a 2mm × 2mm Micro QR M1, it's ~0.18mm — below spec.
Quiet zone. Standard QR requires 4 modules of white space on all sides. Micro QR only requires 2 modules. rMQR requires 2 modules. Most scanners are lenient on Micro QR quiet zones; don't skip them anyway.
ECC unavailable at small sizes. M1 and M2 have no error correction. A single damaged module kills the scan. For anything mission-critical, use M3 or M4 with ECC-M.
rMQR orientation. rMQR has asymmetric finder patterns (two corner + one side). Scanners detect orientation automatically, but printed labels mounted with the short edge UP (vs left) decode 10–15% slower on some firmware. Standardise orientation in your labelling workflow.

Scanner compatibility

Reader	Micro QR	rMQR	Notes
iOS Camera	No	No	Apple supports standard QR only.
Android Camera	No	No	Google also standard QR only.
Google Lens	Partial	No	Some Micro QR sizes decode; rMQR usually doesn't.
Scandit SDK	Yes	Yes	Full support; used in pharma serialisation apps.
Cognex DataMan	Yes	Yes	Full support; industrial machine-vision leader.
Dynamsoft Barcode Reader	Yes	Yes	Full support; common in enterprise Java / .NET workflows.
ZBar / zxing-cpp	Yes	No	Open-source libraries support Micro QR; rMQR support is lagging (active PRs as of 2025).
Industrial handhelds (Zebra, Honeywell, Datalogic)	Yes (firmware-dependent)	Newer models	2023+ firmware usually includes both.

When to use Micro QR or rMQR vs standard QR

Use standard QR when phone-camera scannability matters. Menu QRs, marketing signage, business cards.
Use Micro QR when physical space is extremely tight (<8mm) and a specialist scanner is in the reading loop. PCBs, small medical devices, surgical instruments.
Use rMQR when the labelling strip is narrow and long. Pharma vial sides, cable wrap, narrow pallet labels.
Use Data Matrix instead when you need ISO/IEC 16022 compliance for pharma serialisation (FDA UDI, EU MDR). Data Matrix has broader industrial scanner support than Micro QR.