What QR codes actually encode
A QR code is a machine-readable image of a text string. That string can be a URL, a phone number, an email address, Wi-Fi credentials in the format WIFI:T:WPA;S:NetworkName;P:Password;;, or any plain text you want a phone camera to read. The code itself doesn't know what kind of data it contains — the scanning app interprets the string and decides what to do with it.
QR codes come in versions 1 through 40. Version determines the grid size and therefore capacity. A short URL like https://example.com/go fits comfortably in a version 3 code (29×29 modules). Longer URLs with tracking parameters may need version 5 or higher. The generator handles version selection automatically based on your input — you only need to choose it manually if you have a specific size constraint.
Common use cases
Print materials: business cards, flyers, restaurant menus, product packaging. Rather than printing a long URL, you print a QR code that links to the page. Event check-in: a QR code per ticket that links to registration data. Wi-Fi sharing: encode your network name and password so guests can connect without typing credentials. Store locations, contact cards (vCard format), and payment links all work the same way — any data that a phone needs to act on quickly.
The key constraint is that the URL or data the code points to must stay stable. If the destination page moves or the URL changes after you've printed the code, every printed copy becomes a dead link.
How to generate a QR code
Open the QR code generator, paste or type your URL or text into the input field, and click Generate. The code appears immediately as a PNG you can download. The generator runs client-side — your data isn't sent to a server.
Before downloading, scan the code with your phone camera to confirm it resolves correctly. This takes five seconds and catches encoding mistakes — a mistyped URL or a malformed Wi-Fi string — before anything gets printed. Download the PNG at the highest resolution the tool offers so you have room to scale it up without pixelation.
Size and error correction
For reliable scanning, a printed QR code needs to be at least 2 cm × 2 cm. Smaller than that and low-end phone cameras struggle, especially in poor lighting. The rule of thumb for scanning distance is that the code should be roughly one-tenth the distance from the camera — a code on a poster read from 1 meter away needs to be at least 10 cm wide.
Error correction level determines how much of the code can be damaged or obscured before it becomes unreadable. Level L (7%) is fine for digital-only use where nothing will cover the code. Level M (15%) is a reasonable default for most print. Level Q (25%) or H (30%) is worth choosing if you're putting a logo over part of the code or printing in conditions where smudging is likely — the added redundancy means more of the code can be lost while still scanning correctly. Higher error correction produces a denser, larger code for the same data.
Common QR code mistakes
Encoding a URL that will change. If you link to a page that later moves or a campaign that ends, every printed code becomes broken. Use a stable URL or a URL shortener where you control the redirect, so you can update the destination without reprinting.
Making the code too small for the intended viewing distance. What looks scannable on screen may be too small on a printed label or too large for a phone to frame on a billboard. Test at actual print size before committing to a print run. The other common error is low contrast — the code requires a dark pattern on a light background. Colored QR codes are fine as long as the contrast ratio between the modules and the background stays high.
A working QR code in under a minute
Generate the code, scan it to verify the destination, download at full resolution, and test again at the final print size. The generator handles the encoding; the scan test is the one step that prevents reprints. For linear barcodes — EAN, UPC, Code 128 — the barcode generator covers the same use case in that format.