How to generate QR codes

Generating a QR code takes ten seconds. Generating one that actually scans reliably on a menu, a business card, or a banner — that takes a minute of thought about what’s going inside the code, how big it’ll print, and where it’s going to live. Skip that minute and you’ll be the person whose conference badge nobody can scan. Here’s how to avoid it.

What a QR code actually encodes

A QR code is just a 2D barcode that stores text. Any text — a URL, a phone number, a Wi-Fi password, a plain sentence. The important bit: the more characters you encode, the denser the code becomes, and the harder it is to scan at small sizes or on curved surfaces. A 20-character short URL scans cleanly from across a room. A 200-character tracking URL with UTM parameters becomes a grid of microscopic dots.

Shorten the URL first

If you’re encoding a link, do yourself a favor and shorten it before generating. A Bitly link, a branded short domain, or a clean custom slug on your own site — all three keep the code sparse and scannable. There’s a second benefit: if the destination ever changes, a short URL redirects, but a QR code pointing at the long original is locked in forever on whatever printed material it’s on.

Our QR code generator makes one for any string, but the quality of your code starts with the quality of the URL you feed it.

Error correction levels

QR codes have four redundancy levels: L (7%), M (15%), Q (25%), H (30%). Higher levels let the code survive damage — a smudge, a logo in the middle, a fold — but they also make the code denser for the same data.

• L: clean digital contexts (on a screen, in an email).
• M: the sane default for most print jobs.
• Q: outdoor signage, anywhere that might get dirty or worn.
• H: when you want to put a logo in the center of the code — the logo covers part of the pattern, and H can survive that.

Minimum print size

A reasonable baseline: at error correction M with a short URL (under 30 characters), 1 inch square prints reliably for scanning from 10-12 inches away. Longer URLs or higher error correction push that up. For a poster scanned from across a room, scale proportionally — the rule of thumb is the code should be about 1/10th of the viewing distance.

Smaller is always riskier. If the code has to live on a business card, keep the URL genuinely short and test on real paper, not just on a screen.

Test from 2-3 phones

Before you print 500 of anything, scan the code with at least two different phones — ideally one iPhone, one Android, one older device. Scan from the distance and angle people will actually scan at. About 1 in 10 codes that look fine on screen fail on a real phone in real light. Finding that out after the print run is expensive.

What breaks QR codes in the wild

Three things wreck scans more than anything else. Glossy coatings: a laminated menu under restaurant lighting often reflects right where the code is. Matte finishes scan much better. Curved surfaces: a code on a coffee cup or a water bottle distorts when the surface wraps; keep the code on the flattest face. Low contrast: a dark gray code on a black background is pretty and unscannable. Dark code on light background, period. Inverting the colors works in theory but many scanner apps don’t support it.

One more habit

Print the URL underneath the QR code in small text. Some phones fail, some people don’t know how to scan, and typing a short URL is a one-second fallback. A QR code should complement a URL, not replace it.