Fitts's Law
Design Principles
The bigger and closer a target, the faster you can hit it.
In practice
Fitts's law, from 1954, predicts that the time to move to a target depends on the distance to it and its size — so a large button close to the cursor is fast, a small one far away is slow. It is why primary actions are big, why menus sit at screen edges, why touch targets have minimum sizes, and why putting a tiny close button in a corner is a decision with a measurable cost.
Questions
What is Fitts's Law?
Fitts's law is a predictive model of human movement stating that time to acquire a target is a function of the distance to it and its size.
Why do you use Fitts's Law?
It turns 'make the button bigger' from taste into physics, and it tells you exactly where placement and size are costing people time and errors.
How do you use/apply Fitts's Law?
Make frequent and primary targets large and near the likely cursor or thumb position, use screen edges as infinite-size targets, and keep destructive actions small and far.
When do you use Fitts's Law?
In every layout decision about size and position of interactive elements, especially on touch.
Who uses Fitts's Law?
Interaction designers and anyone laying out controls.
