Generating a QR code is easy — the hard part is making one that actually scans once it's printed. You've probably hit this before: a poster that won't scan after printing, wanting to add your company logo without hiding data, or swapping the plain black-and-white look for colors that some devices refuse to read. These problems almost always come down to four settings: error correction level, quiet zone, size and color. This guide walks through each one with real scenarios.
1. When Scanning Fails, Check These Three Things
- Quiet zone clipped: QR codes need a blank margin around them (at least 4 modules). Trimming the quiet zone during sticker cutting or pushing it under a poster's bleed area is the #1 cause of scan failures.
- Poor contrast: A dark foreground on a light background is the most reliable. Inverted colors or a light-gray code on white are often unreadable by scanners.
- Damaged surfaces: On reflective metal, plastic or wear-prone surfaces, you need a higher error correction level as a safety net.
2. Posters and Print: Sizing and the Quiet Zone
A QR code that looks fine on screen can come out quite differently in print. Keep the quiet zone generous before printing (the generator lets you choose 4 or 8 modules) and use at least 480px for screen output; when you need to scale up, export SVG — the vector format stays crisp at any size.
3. Adding a Logo? Choose the Right Error Correction Level First
| Level | Error correction | Best for |
|---|---|---|
| L | ~7% | Dense content on clean surfaces, screen-only display |
| M | ~15% | Everyday use; handles a small logo |
| Q | ~25% | Larger logos, light soiling |
| H | ~30% | Metal/plastic surfaces, wear-prone conditions |
Keep the center logo within about 22% of the code and give it a white backing — the tool handles this automatically, so level M or above is enough for reliable scanning.
4. Capacity: URLs, Text or Chinese?
QR codes grow capacity through versions 1–10: the longer the content, the higher the version and the denser the pattern. Chinese text is counted as multi-byte UTF-8, so the same number of characters occupies more modules than plain digits. The generator picks the right version automatically and displays the module count and byte size — no manual calculation needed.
5. Export: PNG, SVG or Copy Directly?
- PNG: Universal — great for chat, web pages and presentations.
- SVG: Vector — ideal for print and large-format output.
- Copy PNG: Paste straight into documents and slide decks, skipping the download step.
All of these settings are visually adjustable with live preview in the QR Code Generator, and everything is generated locally in your browser.
Frequently Asked Questions
How much content can a QR code hold?
Capacity depends on the version and error correction level: the longer the content, the higher the version and the denser the pattern. Chinese text is encoded as multi-byte UTF-8, so the same number of characters occupies more modules than plain digits.
Can a QR code with a center logo still scan?
Yes. Choose error correction level M or higher and keep the logo within roughly 22% of the center and it will still read normally. For surfaces prone to dirt or wear, go with Q or H.
Can I change the QR code colors freely?
Use a dark foreground on a light background. Inverted colors and low contrast (such as a light-gray code on white) cause some devices to fail to scan.
Is my generated QR code uploaded to a server?
No. The QR code is generated locally in your browser and nothing is uploaded.
References
- QR Code specification and error correction — ISO/IEC 18004 overview: https://www.qrcode.com/en/about/
- Google's official QR code documentation: https://developers.google.com/chart/infographics/docs/qr_codes