QR code size calculator
How small can a QR code be before it stops scanning? It depends on two things at once: how far away people stand, and how much data the code carries. Enter both and this calculator gives you the printed width in millimetres, the size of a single module, the quiet zone to reserve in your layout and the pixel width for a raster export.
1. Where is it read from?
Seated guest, phone at arm's length. Scanners resolve a code at about 10 times its own width.
2. What does it carry?
33 characters → 29 × 29 modules (version 3). A longer link means smaller modules at the same printed width.
Default for flat, clean printing.
3. Print size
Recommended printed width
30 mm
Absolute minimum 24 mm. Reserve 38.3 mm in the layout to keep the 4-module quiet zone clear.
30 mm
At 30 mm each module is 1.03 mm and the code stays readable up to about 30 cm away.
- Module size
- 1.03 mm
- floor 0.4 mm, safe 0.6 mm
- Quiet zone
- 4.1 mm
- each side, keep empty
- Reads up to
- 30 cm
- at this width
- Raster export
- 354 px
- at 300 DPI — vector is better
Questions
- What is the minimum size for a QR code?
- There is no single number, but the working floor is around 20 mm for a short link read from arm's length, and a module never smaller than 0.4 mm. The two rules to apply are: printed width of at least a tenth of the reading distance, and enough width that each module survives the printing process.
- Why does the same size fail with a longer link?
- A longer payload needs a bigger symbol, so the same printed width is divided into more, smaller modules. Shortening the URL — or using a dynamic code, whose payload is a short redirect — is often cheaper than enlarging the artwork.
- What is the quiet zone and do I really need it?
- It is the empty margin around the symbol, four modules wide, and yes: scanners use it to find where the code ends. Text, a border or a photo edge touching the code is a common cause of intermittent scans.
- Which resolution should I export at?
- For print, use a vector file — SVG or PDF — and resolution stops mattering. If your layout only accepts a raster image, the calculator shows the pixel width for 300 DPI, which is what commercial printing expects.
- Does error correction change the size?
- Yes. Higher error correction adds recovery data, which can push the code to a larger symbol with more modules. Level H — required when a logo covers the centre — is the most expensive in size, so check it here before you commit to the artwork.
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