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A QR code needs clear separation between its dark modules and the light area around them. This contrast checker calculates the relative luminance ratio of two selected colours and warns when the combination may be too subtle for reliable scanning or for people with low vision.
The ratio is a useful screening measure, not a guarantee that every scanner will read the final design. Gradients, reflective paper, transparent backgrounds, and printed colour shifts are not represented by a simple hexadecimal contrast calculation. Test the actual file at its final size.
How to use this tool
- Choose the foreground and background colours.
- Read the computed contrast ratio and guidance.
- Adjust the pair and test the exported code with a phone camera.
Practical guidance
Run the contrast check before applying brand colours to a QR design. Dark navy against a pale background often offers a more dependable starting point than two mid-tone colours, even when both shades look attractive on a display. Keep the area immediately around the QR pattern clear and avoid reflections or transparent materials that alter the apparent background.
Checks before you use the output
The calculator compares digital colour values and cannot simulate every printer, substrate, lighting condition, or camera sensor. A passing ratio therefore does not certify scan reliability. Export the final design, test it on several phones, and repeat the check after any designer adds a logo, gradient, tint, or background image.
Questions and answers
Is a high contrast ratio enough to guarantee scanning?
No. It is a useful signal, but code density, physical size, print quality, and quiet zones also affect scanning.
Can I use two similar brand colours?
You can test them here, but use a much stronger contrast if scan reliability is important.
Does a contrast pass guarantee the QR code will scan?
No. The ratio checks colour contrast only. Code density, quiet zone, size, print quality, glare, and the scanning device all influence the final result.