How to Make a QR Code That Actually Scans: Best Practices

A QR code that looks fine but fails to scan on the poster, menu or business card is a common and avoidable problem. Almost every failure comes down to a handful of rules.

How a QR code stores data

A QR code is a grid of black and white squares (modules) that encodes text, usually a URL. Three large squares in the corners let the camera find the code and work out its orientation. The more data you encode, the more modules the code needs, and the smaller each module becomes for a given print size, and small modules are harder to read.

Short content makes a simpler code. A short URL yields a code with big, chunky modules that scans quickly from further away. A long URL with tracking parameters produces a dense code that needs a steady hand and good light.

Minimum size and scanning distance

A widely used rule of thumb is distance ÷ 10: a code should be at least one tenth as wide as the distance from which it will be scanned. For a code read from 1 metre away, that means about 10 cm. On a business card, held in the hand, 2 cm × 2 cm is workable if the content is short. For posters and shop windows, size up accordingly.

Contrast and colour

• Dark on light is the most reliable. Black on white is best.
• Inverted codes (light on dark) are not read by every scanner, so avoid them when you can't test on many devices.
• Colours work if the contrast is strong. A dark blue on white is fine; yellow on white is not.
• Avoid gradients and busy backgrounds behind or inside the code.

Quiet zone

Leave an empty margin around the code, at least four modules wide, called the quiet zone. Text, borders or images that touch the code make it much harder to detect. When you design a poster, treat the margin as part of the code.

Error correction and logos

QR codes include redundancy so that they can be read even if part is dirty, damaged or covered. There are four levels:

• L — recovers about 7% of the data
• M — about 15%
• Q — about 25%
• H — about 30%

Higher levels make the code denser. Use M for clean screens and paper, and Q or H for codes with a logo in the middle, or that will sit on stickers or outdoor surfaces. Keep a logo small, well under a quarter of the code's area, and test it. A logo that covers too much area breaks the scan however high the correction level.

Static versus dynamic codes

• Static codes encode the destination directly. They are free, never expire and work forever, but you can't change the destination after printing.
• Dynamic codes point to a redirect service that you can change later, and often show scan statistics. The catch is that they stop working if the subscription ends, so beware of paid "free trial" services that hold your printed codes hostage.

Codes generated here are static: what you enter is what is encoded, and nothing is routed through our servers.

What you can put in a QR code

• URLs — the most common. Always include https://.
• Wi-Fi details — guests scan to join without typing a password.
• Contact cards (vCard) — for business cards.
• Plain text, email, phone and SMS links.

Test before you print

1. Scan with at least two different phones, one older.
2. Scan from the real distance and in the real lighting.
3. Print a proof at the actual size before sending a large run.
4. Check that the destination works on mobile data, not only on your Wi-Fi.

PNG or SVG?

Use SVG for print, as it is vector-based and stays sharp at any size, from a business card to a banner. Use PNG for screens and documents, exporting at a generous resolution so that it doesn't blur when scaled.

Staying safe

QR codes are also used in scams: stickers placed over legitimate codes, or fake parking-payment codes. When you scan an unfamiliar code, look at the URL your phone shows before opening it, and never enter payment details on a page you reached from a code in a public place. If you publish codes, place them where they can't easily be covered.

Frequently asked questions

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