# QR code design best practices — seven rules ranked

> Seven rules cover almost every design failure. Keep a 40% luminance difference with dark modules on light, preserve a four-module quiet zone, size the code at one tenth of scan distance, leave the three corner squares intact, cap logos near 20% at error correction H, style modules without merging them, and decode the finished artwork before printing.

Source: https://useqr.app/docs/design/qr-code-design-best-practices · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## Seven rules, ranked by kill rate

Almost every styled QR code that fails in the wild breaks one of seven rules. They are
ranked here by how often violating them is the actual cause of a dead code, not by how
often designers worry about them — the two orders are nearly opposite.

| # | Rule | The number | Break it and |
|---|---|---|---|
| 1 | Dark modules on a light background | ≥ **40%** luminance difference | the code is unreadable everywhere |
| 2 | Quiet zone | ≥ **4 modules**, all four sides | detection fails intermittently |
| 3 | Size for distance | width ≥ distance ÷ **10** | scans in hand, fails on the wall |
| 4 | Leave the three eyes findable | **1:1:3:1:1** ratio intact | the scanner never locates the code |
| 5 | Logo inside the budget | ≤ ~**20%** coverage at EC H | works on screen, dies in print |
| 6 | Style without starving modules | ≥ ~**60%** ink per module, never merged | fails at small sizes |
| 7 | Verify the final artwork | decode the actual export | all of the above ship unnoticed |

## Contrast and polarity (rules 1)

Decoders threshold on luminance, not hue, so any brand colour works if it is dark
enough — the working minimum is a [40-point luminance difference](/docs/design/qr-code-contrast-ratio-minimum)
against the background, and the safe target is above 60. Put the colour on the modules
and leave the background white; [light-on-dark codes fail](/docs/design/why-light-on-dark-qr-codes-fail)
on a meaningful share of scanners because inversion support is inconsistent.

## Space and size (rules 2–3)

The [quiet zone](/glossary/quiet-zone) is four clear modules on every side — frames,
text and page edges all count as violations. Size follows the 10:1 rule: a code read
from 2 m needs to be at least 20 cm wide. The [size calculator](/size-calculator) does
the arithmetic for any distance, and close-range print has a hard floor of 2 × 2 cm.

## Structure (rule 4)

The three corner squares are how a scanner finds the code before error correction does
anything. Restyle them with intent — rounded, circle and leaf variants survive because
they keep the 1:1:3:1:1 scanline ratio — but never cover them, fade them, or open the
ring. [Custom eye shapes](/docs/design/custom-eye-shapes) explains which variants carry
which risk.

## Logos and module styling (rules 5–6)

A centred logo is spent error-correction budget: keep it near
[20% coverage at level H](/docs/design/logo-size-limits-by-error-correction-level) and
give it a clear panel. Module restyling is safe when every module keeps roughly 60% of
its ink and no neighbouring modules merge — the
[shape comparison](/docs/design/qr-code-module-shapes-compared) ranks square, rounded,
dot, bar and organic styles by that margin.

## Verify (rule 7)

Rules 1–6 fail silently: the artwork looks fine and simply does not scan. The fix is
mechanical — run the finished export through the [validator](/validate), which renders
the code and reads it back with a real decoder, before anything goes to print. UseQR
does this automatically on every download, but re-check after any edit in a design tool.

## FAQ

### What is the most common QR code design mistake?

Insufficient contrast, usually from colouring the background instead of the modules or
using a light brand colour like yellow or orange for the modules. It kills more codes
than logos, styling and sizing errors combined, and it fails on every scanner rather
than just some.

### Can I style every part of a QR code?

You can restyle module shapes, eye shapes, and colours freely within the contrast and
fill limits. The parts you must not alter are structural: the three finder squares'
proportions, the timing lines, and the four-module quiet zone around the whole symbol.

### How much of a QR code can a logo cover?

About 20% of the area at error-correction level H, placed centrally on a clear panel.
At the default level M, keep it under about 10%. The theoretical ceilings are higher,
but print damage and camera angle draw on the same budget.

### How do I check a designed QR code still scans?

Decode the final exported file, not the on-screen preview. A validator that rasterises
and reads the artwork back catches contrast, logo and styling failures in seconds, and
testing a printed proof under poor light catches the rest.

## Try it

- https://useqr.app/url
- https://useqr.app/validate
- https://useqr.app/size-calculator