Touch Target Accuracy Tester
Compare touches with target positions.
Tap, click or press Space to keep count.
Tap anywhere inside or press Space
How the Touch Target Accuracy Tester Works
The Touch Target Accuracy Tester shows a target, measures the distance between your touch and the target center, and reports the average error in pixels and millimeters.
- Tap the target: A circle appears at a random spot. Tap its center.
- Measure the error: The tool calculates the distance from the touch to the center.
- Repeat for each target: Run 20 to 50 targets across the screen.
- Read the results: See hit rate, mean error and the direction you drift most.
Touch Target Accuracy Tester Formula
The Touch Target Accuracy Tester error equals the straight-line distance between the touch point and the target center. Mean error equals the sum of errors divided by the number of trials.
- x_touch, y_touch
- Touch position
- x_target, y_target
- Target center
- Trials
- Number of targets shown
Example: A touch lands at (212, 309) on a target centered at (200, 300). Error = √(144 + 81) = 15 px, or 4.0 mm (0.16 in).
Touch Target Accuracy Tester Reference Table
The Touch Target Accuracy Tester conversion table converts touch error into millimeters and inches and rates the result.
| Error (px) | Error (mm) | Error (in) | Rating |
|---|---|---|---|
| 4 | 1.1 | 0.04 | Excellent |
| 8 | 2.1 | 0.08 | Very good |
| 12 | 3.2 | 0.13 | Good |
| 20 | 5.3 | 0.21 | Fair |
| 30 | 7.9 | 0.31 | Poor |
| 40 | 10.6 | 0.42 | Very poor |
About the Touch Target Accuracy Tester
A Touch Target Accuracy Tester is a test that measures how close touches land to intended targets. The result shows both user precision and screen calibration.
Research on finger touch finds a typical error of 2 to 4 mm for adults tapping a small target. Touch errors grow near the screen edges and with one-handed thumb use, which is why guidelines set minimum target sizes of 44 to 48 px.
Ways to Use the Touch Target Accuracy Tester
The Touch Target Accuracy Tester has 5 key uses, including target size planning and calibration checks.
- Target size planning: Designers set button sizes from measured error.
- Calibration checks: Technicians spot screens that report touches offset from the finger.
- Motor skill tracking: Therapists measure precision across sessions.
- Stylus comparison: Users compare finger error with pen error.
- Gaming accuracy drills: Players train aim on mobile shooters.
Tool Details
- Category
- Touch & Gesture Diagnostics
- Controls
- Taps and keys
- Input Support
- Touch, Pen, Mouse, Keys
- Offline Ready
- On your device