Touch Target Error Rate
Simulate accidental miss probability (Fat Finger).
Based on MIT Touch Lab studies, the average adult index finger pad is ~16-20mm, and the thumb is ~25mm. When UI targets dip below 9mm (roughly 48dp), error rates scale exponentially.
| Target Size | Est. Error Rate |
|---|---|
| 48dp (9mm) | < 1% |
| 32dp (6mm) | ~ 5% |
| 24dp (4.5mm) | ~ 15% |
| 16dp (3mm) | > 30% |
Interactive Visualization
CTA
Avg Thumb
Visualizing a 25mm (approx 60px) thumb touch area overlapping a 24px button. Any adjacent buttons within the red circle are at high risk of accidental activation.