QR code for a business card

The length of your link decides how fine the code gets

A QR code does not grow when it holds more data — it subdivides. More characters means more modules inside the same square, and every module gets smaller. On a business card, where the code is perhaps 20 mm across, that is the constraint that actually matters.

These are real figures from the encoder this tool ships, at standard error correction, including the four-module quiet zone a code needs on every side:

1. https://torelya.com — 19 characters, a 25×25 grid, 0.61 mm per module at 20 mm.
2. https://www.mybarbershopexample.com/booking — 42 characters, 29×29, 0.54 mm.
3. The same link with campaign parameters attached — 91 characters, 41×41, 0.41 mm.

Which is why the cheapest fix is a shorter link

That last code has modules a third smaller than the first, for a link that opens the same page. Phone cameras handle all three on good paper — but the margin for a fold, a thumbprint or an uncoated stock disappears quickly.

Raising the error correction costs you the same way, because robustness and density are one dial: at the higher level, the 91-character link becomes a 49×49 grid and 0.35 mm per module.

So the first thing to fix is not the size of the code. It is the length of what goes in it.

What to point it at

The instinct is to link the homepage. Usually something more specific is worth more, because a card is handed over in a situation you already understand.

A tradesperson hands the card to someone who will want to message — point it at WhatsApp, with the first line already written. A stylist or a therapist hands it to someone who needs to book: point it at the booking page. A photographer hands it to someone who wants to see work: point it at the portfolio, not the front page. A shop points it at Instagram, where the pictures already are.

Whatever you choose, prefer a URL on a domain you control. A link to a platform account is a link you might not own in two years, and by then there are five hundred cards in circulation.

The margin is part of the code

The most common way a business card code fails has nothing to do with size. It is the white border. That quiet zone — four modules wide on every side — is what tells a scanner where the pattern stops, and on a card layout it looks exactly like wasted space.

Trim it, run a background colour into it, or push the code to the edge of the card, and it reads slowly or not at all. Leave the margin, and keep the whole code clear of the trim edge as well: guillotines are not exact, and a code that is fine in the file can be cut into on press.

Contrast, and why the brand palette is often the enemy

Dark code on a light background. That is the whole rule, and cards break it constantly, because a code in the company grey on the company off-white looks tasteful and scans badly.

Inverting — a light code on a dark card — is the other trap. Some scanners cope, others do not, and you find out after the print run. The generator checks the pair you choose and tells you before you download.

A logo in the middle is fine within limits, and those limits are measured rather than guessed: the tool works out how much of the code’s error-correction margin the logo is consuming, and blocks the download when it goes past what the code can still recover from.

Send the printer a vector file

Send the SVG or the PDF, not a PNG. Both are vector, so the code is defined as shapes rather than pixels and stays exact at whatever size the layout sets. A PNG dropped into a design and nudged three per cent larger is how sharp module edges become grey fringes.

If a raster is unavoidable, give the designer the largest PNG the tool offers and let them scale down, never up.

The PDF also exports at an exact physical size, so 20 mm across means 20 mm on the finished card rather than whatever the layout software decides.

Before you order five hundred

Print one card, on the real stock, at the real size. Then scan it with an ordinary phone in ordinary light, at arm’s length, at an angle — not with your own phone under a desk lamp.

Check the link opens the page you meant on a phone that is not signed into anything of yours. A code that quietly opens your own admin view because you happened to be logged in is a mistake that survives the entire print run.

And be clear about what a static code is. The destination sits inside the pattern, so it cannot be repointed later. That is why there is nothing to subscribe to and nothing that expires — and equally why the URL is a decision rather than a placeholder.