Interaction & Behavior
Fitts's Law
Time to reach a target depends on its size and distance.
Takeaways
- 1
Primary actions should be large and easy to acquire.
- 2
Place frequent controls near the user’s likely focus area.
- 3
Separate destructive actions from primary ones.
Origins
Paul Fitts modeled human movement as a tradeoff between distance and target size. In digital interfaces, the same relationship applies to cursors, thumbs, and styluses.
Small or distant controls increase error rates and slow completion times, especially on touch devices.
Design Applications
- Use at least 44px touch targets for key actions.
- Keep primary buttons wide enough for confident tapping.
- Put frequent actions in thumb-friendly zones on mobile.
Frequently Asked Questions
What is the Fitts's Law?
Time to reach a target depends on its size and distance.
How do you apply Fitts's Law in UI design?
Use at least 44px touch targets for key actions. Keep primary buttons wide enough for confident tapping. Put frequent actions in thumb-friendly zones on mobile.
Why does Fitts's Law matter for user experience?
Primary actions should be large and easy to acquire. Place frequent controls near the user’s likely focus area. Separate destructive actions from primary ones.
