QR Code Readability Checker

A tool that evaluates your QR code's real-world scan reliability across multiple factors — size vs scan distance, error correction level, logo coverage, contrast ratio, quiet zone, and print quality — and returns a readability score (0-100) with specific fixes for each issue. It's the pre-flight check before you print 500 business cards or a large-format banner.

7 weighted factors: Size vs Distance (25 pts, 1:10 rule compliance), Error Correction (20 pts, appropriate level for use), Contrast Ratio (20 pts, WCAG AA 4.5:1), Quiet Zone (15 pts, 4-module ISO spec), Logo Coverage (10 pts if present), Finish (5 pts, matte vs glossy), Print DPI (5 pts, per-distance floor). Each factor is pass/warning/critical, combined into a 0-100 score.

90+ is excellent — the QR is reliable across devices and conditions. 75-89 is good but has a warning worth addressing. 60-74 is fair — one critical issue will cause scan failures on older phones or in adverse conditions. Below 60 is risky to print. Below 40 is likely to fail in production. Always address critical issues before committing to a print run.

Black on white = 21:1 (ideal). Dark-colored QRs on white backgrounds (navy, dark red, dark green) typically hit 7-15:1, which is fine. Light-colored QRs (light gray, pastels) on white backgrounds often fall below 3:1 and fail. Use a contrast checker like WebAIM's tool — target 4.5:1 minimum (WCAG AA) for reliable scanning across phone cameras.

The quiet zone is the empty margin around the QR code that scanners use to detect the code's boundary. The ISO/IEC 18004 specification requires 4 modules (QR unit squares) of empty space on all four sides. Without sufficient quiet zone, scanners fail to locate the QR even if the internal pattern is perfect. Our checker flags quiet-zone violations because they're one of the most common preventable failures.

Up to 25% of the QR's area at H-level (30%) error correction, but the safe recommended zone is 18-20%. Larger than 25% and scan reliability drops sharply even on H-level. Our checker warns at 20%+ and flags critical at 25%+. For detailed logo rules see our QR with logo tutorial.

Yes. Logos replace data modules that the scanner needs to read. H-level (30% recovery) provides enough redundancy to tolerate a 20% logo overlay plus real-world wear. L or M error correction with a logo pushes the error rate over the recovery ceiling — QR becomes unscannable on about half the devices that try. Our checker flags this as a critical issue.

Glossy finishes create hot-spot glare under directional lighting (direct sun, overhead fluorescents) that blanks out part of the QR pattern in the camera's view. Matte finishes diffuse light evenly and scan reliably. The impact is biggest on outdoor signage and trade-show displays. Our checker warns if you use glossy finish at distances where glare becomes likely.

Scales with scan distance. Close reading (under 12 inches): 300 DPI minimum — module edges must be crisp. Standing distance (1-4 feet): 200 DPI. Drive-by (4-8 feet): 150 DPI. Billboard (20+ feet): 96 DPI suffices. Our checker compares your configured DPI to the distance-appropriate floor. Always export as SVG when possible — vectors scale cleanly to any DPI.

Yes — this is exactly the pre-flight check it's designed for. Enter your QR size (typically 0.8-1.0 in), scan distance (6-10 in for business cards), error correction (H if using a logo), and contrast values. The tool flags anything that'll fail before you commit to a print run of 500 cards.

Not always — but it means scan reliability drops significantly, especially on older phones, in poor lighting, or with slightly damaged prints. A 60 score might scan fine 70% of the time under ideal conditions and fail 40% of the time in real use. For marketing materials you send to thousands of prospects, "70% scan rate" is costly. Target 90+ for anything you're printing at volume.

Just upload. The tool decodes your QR image in the browser using jsQR, then analyzes the pixel data to infer the foreground color, background color, logo presence, and QR density. No server upload, no account — your image stays in your browser. For QR design choices we can't detect from an image alone (error correction level, module style), we assume conservative defaults and flag logo-present QRs as high-risk if they weren't built at H-level error correction.

A pre-production reliability test: print or display your QR at final spec, then scan with 3 phones (iPhone, Android, and one 3+ year-old phone) at 3 distances (close, target, far) under 3 lighting conditions (bright outdoor, dim indoor, mixed office). That's 27 scenarios — run 20 randomly chosen. Target 95%+ first-attempt scan success. Any scenario failing repeatedly = redesign before commit.