QR Code Size Calculator
Enter what the code will contain and the calculator returns the module size, the symbol size, the quiet zone and the pixel dimensions to export. The maths comes from DENSO WAVE, the company that invented the QR code: module size = 25.4 ÷ dpi × dots per module, and every symbol needs a four-module quiet zone on all four sides.
Paste the real content — length decides the version, and the version decides the size.
Higher levels survive damage but need more modules at the same content length.
A rule of thumb, not a standard: code width ≈ distance ÷ 10.
300 dpi for print, 72 for screen.
The formula
module size (mm) = 25.4 ÷ dpi × dots per module · symbol = modules × module size · total = symbol + 8 × module size
Formula, the four-module quiet zone and the scanner resolution limits come from DENSO WAVE, the company that invented the QR code. qrcode.com
How QR code size is actually determined
Size is not a design choice you make first — it falls out of three things in order. The content length and error correction level decide the version, the version decides how many modules sit along each side, and the module size decides how many millimetres those modules occupy.
DENSO WAVE gives the worked example: 50 alphanumeric characters at error correction M needs version 3, which is 29 modules per side. Printed at 400 dpi with 4 dots per module, each module is 25.4 ÷ 400 × 4 = 0.254 mm. So the symbol is 29 × 0.254 = 7.366 mm, and with the quiet zone the required area is 9.398 mm square.
This is why shortening the content shrinks the code more than any layout tweak. Cutting a long URL to a short redirect can drop several versions, and each version removed takes four modules off every side.
What about the 10:1 rule?
The widely quoted rule is that a code should be about a tenth as wide as the distance it will be scanned from — 30 mm for 300 mm, and so on. It is a useful starting estimate and this page reports it.
It is not a standard, though, and pages that present it as one are overstating it. Scanning distance depends on the camera, the lighting, the print contrast and how steady the hand is. Treat the number as a first guess to be confirmed with a printed proof, not as a specification.
The figures that are specified are the ones this calculator warns on: DENSO WAVE puts the readable module size at 0.25 mm for a standard handheld scanner and 0.1 mm for a high-resolution one, and recommends at least four printer dots per module for stable printing.
Why the quiet zone is not optional
The four-module margin around the pattern is part of the code, not decoration around it. A scanner uses that blank border to find where the symbol begins; without it the pattern often cannot be located at all, and the failure looks random rather than systematic.
This is the single most common cause of codes that "worked in the design file" and fail in print. Legal text, a bleed edge, a fold or a logo creeps into the margin and the code stops being found. The calculator reports the quiet zone as a separate figure for exactly this reason: it is a dimension to reserve, not a suggestion.
Frequently asked questions
What is the minimum print size for a QR code?
There is no single number, because it depends on how many modules the code has. What is fixed is the module: below roughly 0.25 mm a standard handheld scanner stops reading reliably, and below 0.1 mm no scanner will. Multiply your minimum module size by the module count plus eight for the quiet zone, and that is your floor.
How big should a QR code be on a business card?
A short link at error correction M is usually version 2 or 3, so 25 to 29 modules. At 2 cm across that gives a module of roughly 0.5 to 0.6 mm, comfortably above the reading limit. The constraint on a card is usually not the code but the quiet zone, which has to stay clear of the text around it.
Does higher error correction make the code bigger?
At the same content length, yes. Error correction adds redundant data, which can push the code to a higher version and therefore more modules per side. If space is tight, shortening the content buys you more room than lowering the correction level does.
What resolution should I export a QR code at?
For print, size the image so the physical dimensions land at 300 dpi or better — the calculator gives the pixel figure. For screens, 72 dpi is enough. Better still, export SVG for print: it has no resolution at all and stays sharp at any size.
Can I make a QR code smaller by removing the white border?
No. The border is the quiet zone and it is part of the specification — four modules on every side. Removing it does not make the code smaller in any useful sense; it makes it harder to find, and scanners frequently fail to locate the symbol at all.