# QR code size for a poster

> Size a poster QR code at one tenth of the real viewing distance — 5 cm for a noticeboard read at 50 cm, 10 cm for a corridor at 1 m, 20–30 cm across a room at 2–3 m. Keep the code in the poster's lower half at eye height, because mounting height adds distance and angle.

Source: https://useqr.app/docs/print/qr-code-size-for-a-poster · Last reviewed 2026-08-21 · UseQR is free forever, MIT licensed, no signup.

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## Match the size to the placement

A "poster" spans everything from an A4 sheet on a noticeboard to an A0 sheet across a
lobby, and the code size follows the viewing distance, not the paper size:

| Placement | Viewing distance | Minimum code | Typical format |
|---|---|---|---|
| Noticeboard, read face-on | 50 cm | 5 cm | A4 |
| Corridor wall | 1 m | 10 cm | A3 |
| Room wall at eye level | 2 m | 20 cm | A1 |
| Lobby, stage backdrop | 3 m | 30 cm | A0 or larger |

A 10 cm code on an A4 poster looks enormous — nearly half the width. Print it anyway. An
oversized code costs a little elegance; an undersized one costs every scan. Most poster
codes in the wild are 2–3 cm, sized for a flyer in the hand rather than a wall at 2 m,
which is why they go unscanned. The arithmetic behind the ratio is in
[the ten-to-one rule](/docs/print/the-10-to-1-distance-rule).

## Mounting height is part of the distance

The 10:1 measurement is camera-to-code, not viewer-to-wall. Put a code at the top of an A1
poster whose centre hangs at 1.9 m and a viewer standing 2 m back with eyes at 1.6 m is
actually about 2.2 m from the code — and looking up at it, so the modules foreshorten
vertically. Both effects spend margin you wanted for lighting and focus.

The fix costs nothing: **place the code in the poster's lower half, between 1.2 and
1.7 m off the floor**, face-height for someone standing close. Where that fights the
layout, follow the guidance in
[QR placement in a layout](/docs/design/qr-code-placement-in-a-layout) rather than
shrinking the code to fit a corner.

## Payload and error correction

- **EC M** is the default for posters; use **EC H only when a
  [logo](/docs/design/qr-code-with-logo-best-practices) sits in the code**, since the extra
  redundancy raises the version and shrinks modules at a fixed size.
- Keep the URL short. A 25-character URL at EC M is a 25-module code; at 20 cm printed
  width each module is a generous 8 mm.
- Give the code a caption that says where it leads. A poster is read in passing, and a
  [clear call to action](/docs/marketing/qr-code-call-to-action) decides whether anyone
  stops for the three seconds a scan takes.

Surface-specific advice — paper stocks, mounting, indoor vs outdoor — lives on the
[posters surface page](/qr-codes-on/posters); the
[outdoor durability guide](/docs/print/qr-codes-outdoors-durability) covers laminates and
sun. For sizing, run your payload and distance through the
[size calculator](/size-calculator), and [check the artwork decodes](/validate) before the
print run.

## FAQ

### How big should a QR code be on a poster?
One tenth of the viewing distance — 5 cm for a noticeboard at 50 cm, 10 cm for a corridor at 1 m, 20–30 cm for a wall read from 2–3 m. Most poster codes are printed far smaller than this and are never scanned.

### How big should a QR code be on an A4 poster?
If the poster hangs where people stand about a metre away, 8–10 cm. That is close to half the sheet's width, which looks large but is what the distance demands.

### Where should a QR code go on a poster?
In the lower half, roughly 1.2–1.7 m off the floor once hung, with the full quiet zone kept clear. Codes placed high on the sheet gain distance and angle that the sizing maths then has to absorb.

### What error correction level should a poster QR code use?
M, unless a logo overlays the code, in which case H. Higher error correction raises the module count, so on a fixed-size code it shrinks every module — the opposite of what distance scanning needs.

## Try it

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