# Micro QR codes: the small variant and its big trap

> Micro QR is the small-format variant of the QR standard - four sizes from 11 x 11 to 17 x 17 modules, one finder pattern instead of three, a two-module quiet zone, and a ceiling of 35 numeric characters. Industrial scanners read it reliably; most phone cameras do not, so never use it for consumers.

Source: https://useqr.app/docs/basics/micro-qr-code · Last reviewed 2026-08-21 · UseQR is free forever, no signup.

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## What Micro QR is

Micro QR is defined in the same standard as regular QR
([ISO/IEC 18004](/docs/basics/qr-code-standards-iso-18004)) as a deliberately stripped-down
sibling for tiny surfaces. Three changes make it small:

- **One [finder pattern](/glossary/finder-pattern)** in a single corner, instead of three.
- **A two-module [quiet zone](/glossary/quiet-zone)**, instead of four modules on every side.
- **Minimal format overhead**, fewer function modules spent on metadata.

The savings are dramatic at this scale. The smallest Micro QR occupies 15 × 15 modules
including its quiet zone; the smallest standard QR needs 29 × 29. Same module size, about
a quarter of the area.

## The four sizes

| Version | Modules | Error correction | Max numeric | Max alphanumeric | Max bytes |
|---|---|---|---|---|---|
| M1 | 11 × 11 | detection only | 5 | n/a | n/a |
| M2 | 13 × 13 | L, M | 10 | 6 | n/a |
| M3 | 15 × 15 | L, M | 23 | 14 | 9 |
| M4 | 17 × 17 | L, M, Q | **35** | 21 | 15 |

(Capacities shown at level L where correction applies.) Note what is missing: M1 can only
*detect* errors, not correct them; M1 and M2 cannot hold bytes at all, so no URL will ever
fit; and even M4's 15-byte ceiling rules out anything beyond a serial number or short code.
Level H does not exist in Micro QR, so heavy damage tolerance is off the table too.

## The trap: phones do not read it

Here is the part that catches people. Micro QR support in consumer scanning is poor:
stock camera apps on iPhone and Android are built around standard QR detection, which
looks for three finder patterns, and most simply never see a Micro QR. Industrial imagers
and many software libraries handle it fine, but the code on your product will meet your
customer's camera, not your library.

**The rule: if a member of the public will scan it, Micro QR is the wrong format.**

## What to use instead

For small consumer-facing codes, a **version 1 standard QR** (21 × 21 modules) is almost
always the honest answer. With a short payload it stays coarse, every phone on earth reads
it, and at the [2 × 2 cm close-range print floor](/docs/print/minimum-qr-code-size) the
size difference against Micro QR is a few millimetres. Keep the payload short (a compact
URL, not a tracked monster), and the code stays scannable;
[the density page](/docs/spec/qr-code-density-and-scan-distance) explains the mechanics.

Micro QR earns its place where its designers aimed it: electronics, instrument marking,
medical devices and other industrial contexts where *you* specify the scanner. For long
thin surfaces in the same world, its rectangular successor
[rMQR](/docs/basics/rmqr-rectangular-micro-qr) carries far more in a strip format.

Whichever you pick, [verify the symbol decodes](/validate) with the actual reading
hardware before committing to a production run.

## FAQ

### What is the difference between Micro QR and a normal QR code?
Micro QR uses one finder pattern instead of three, a two-module quiet zone instead of four, and comes in four sizes from 11 x 11 to 17 x 17 modules. It holds at most 35 digits or 15 bytes, against a standard QR code's thousands.

### Can a phone scan a Micro QR code?
Usually not. Stock camera apps detect the three-finder geometry of standard QR and mostly ignore Micro QR. Industrial scanners and some dedicated apps read it, which is why it belongs only in controlled environments.

### How much data fits in a Micro QR code?
The largest version, M4 at 17 x 17 modules, holds 35 numeric characters, 21 alphanumeric characters or 15 bytes at the lowest error correction level. The smallest, M1, holds just 5 digits with no error correction.

### When should I use Micro QR instead of a small standard QR code?
Only when marking area is critically scarce and you control the scanners, such as electronics or instrument marking. For anything the public scans, a version 1 standard QR code is only slightly larger and universally readable.

## Try it

- https://useqr.app/text
- https://useqr.app/url
- https://useqr.app/validate