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QR Readability Score Calculator

Combine size, contrast, density, and lighting into one 0–100 readability score with a grade and the weakest factor to fix. This is a composite planning score from your inputs, not a measured scan rate, and it does not replace the single-factor checkers.

1. Rate the four factors

100% = exactly the recommended size. Below 100% is undersized; above is oversized.

Formula: score = 0.30 × size sub-score + 0.30 × contrast sub-score + 0.20 × density sub-score + 0.20 × lighting sub-score. Contrast sub-score maps 1:1 → 0 and 21:1 → 100 linearly. Grades: A ≥ 85, B ≥ 70, C ≥ 50, D ≥ 30, else F.

Result
Readability score
73 / 100
Grade: B — Good
Size (30%)100
Contrast (30%)45
Density (20%)70
Lighting (20%)75
Fix firstContrast (45)

One Weak Factor Can Sink a Code

Readability is not an average of good intentions: a huge, high-contrast code in blinding glare can fail, and a perfect code printed too small fails too. A composite score is useful because it forces all four factors onto one page and names the weakest one. Fix the bottleneck first — improving an already-strong factor while the weakest stays weak barely moves the result.

Use it to compare designs

Score each candidate design with the same assumptions and pick the highest score. Then confirm with a printed proof scanned on two phones in the real lighting — the score guides the choice, the test-scan proves it.

Frequently Asked Questions

Is this score a measured scan rate?

No. It is a composite planning score computed from the four factors you enter, weighted 30% size, 30% contrast, 20% density, 20% lighting. It ranks designs and flags the weakest factor — it does not predict a measured scan rate.

What does "size vs distance" mean?

How large the printed code is compared with the size it needs at its viewing distance. 100% means the code is exactly the recommended size for the distance; above 100% it is larger than needed (better), below it is undersized.

Why is contrast capped at 21:1?

21:1 is the maximum WCAG contrast ratio (pure black on pure white). The contrast sub-score maps your entered ratio linearly from 1:1 (score 0) to 21:1 (score 100).

My score is low. What do I fix first?

Fix the weakest factor shown in the result — it is the bottleneck. Raising an already-strong factor while the weakest stays low moves the total only a little.