This free calculator gives the smallest QR code or barcode size that still scans reliably. For a QR code, enter how far away it will be scanned, how much data it holds, and the error-correction level, and it returns a minimum printed width in millimetres and pixels, the QR version, and the module size, using the module and quiet-zone rules from Denso Wave and ISO/IEC 18004. For retail barcodes it applies the GS1 magnification range.
Based on Denso Wave, ISO/IEC 18004, and GS1 specs. The 10:1 distance rule is an industry heuristic, not a standard - test-scan a printed copy before a full run.
Switch between the QR calculator and the 1D barcode calculator (EAN-13/UPC-A or Code 128).
For a QR: scanning distance, data length, and error correction. For a retail barcode: the magnification you plan to print at.
You get the smallest reliable width in mm, cm, inches, and px, plus the version and module size. Test-scan a printed copy before a full run.
Two limits set the minimum, and the calculator takes whichever is larger. The distance rule of thumb says a QR code reads from up to about ten times its own width, so a code scanned from 30 cm wants to be at least 3 cm across. The second limit is the module: each small square has to survive printing and a phone camera, and about 0.4 mm is the smallest module most phones read reliably. The tool sizes the QR version from your data length and error-correction level (more data or higher correction means more modules, which means a bigger code at the same module size), then adds the mandatory four-module quiet zone. One honesty note: the 10:1 distance figure is an industry heuristic, not part of ISO/IEC 18004. The rigorous floor underneath it is a scanner needing at least 2.5 pixels per module, per the machine-vision maker Cognex.
EAN-13 and UPC-A are defined at a nominal 100% size, a 0.330 mm bar-width unit and about 37.3 mm wide, and they scale from 80% to 200% under the GS1 specification. Below 100% you need clean on-demand printing, and 80% is only safe on thermal or laser. Code 128 for general distribution uses a 0.495 mm minimum bar-width unit with a quiet zone of at least ten times that on each side. The calculator returns those figures so a label fits its space without dropping below what a scanner can read.
Sizing is only half the battle. If the destination changes, a static code is dead paper. Whooshly's dynamic QR codes let you re-point a printed code to a new URL and see scans by device and place, all on the pay-once $49 toolkit. Size it here, then make it editable.
For a phone scanned at arm's length (about 30 cm), roughly 2 to 3 cm square is the practical minimum, and 10 mm is the absolute floor. The real driver is the module size: keep each square at about 0.4 mm or larger. More data or a higher error-correction level needs more modules, so the code has to be physically bigger to hold that module size.
Use the distance rule: a QR code reads from up to about ten times its width. A poster scanned from 2 metres wants a code around 20 cm across; a billboard read from 10 metres wants about 1 metre. Enter the real scanning distance in the calculator and it does the arithmetic.
Yes. Longer data needs a higher QR version, which adds modules: a version 1 code is 21x21 modules, version 10 is 57x57. At a fixed module size, more modules means a physically larger code. Shortening the URL, or pointing at a short redirect link, keeps the code smaller and easier to scan.
The nominal 100% size is about 37.3 mm wide with a 0.330 mm bar-width unit, and GS1 allows 80% to 200% of that. Going below 100% requires good on-demand printing, and 80% is only reliable on thermal or laser printers. Keep the light margins (quiet zones) on each side.
Usually the modules dropped below what the camera can resolve, the quiet zone got cropped, or a stretched PNG blurred the squares. Export as SVG so it stays sharp at any size, keep the four-module margin, and check the minimum width here before you print.
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