Fitts’s law

The time it takes us to point at something grows the farther away it is and the smaller it is.

What problem it addresses

Explains why small or distant buttons are hard to hit, and why important ones should be large and within reach.

The pay button in an online store, on your phone.

Small and far

A small link at the very top, far from the thumb. Hard to hit.

Large and close

A wide button at the bottom, where the thumb rests. You tap it without looking.

What the button does doesn't change; what changes is how much effort it takes to reach it.

A fast movement is imprecise.
The smaller and farther away the target, the more you have to slow down and correct.
Each correction adds time.

Use it like this
Make the most used buttons large and close.
Avoid
Putting the main action small and in a hard-to-reach corner.
Don’t fall for it
Placing two opposite actions, like “Save” and “Delete”, very close together makes it easy to press the wrong one.

0.18 s vs. 0.73 s

That was the average time per tap with a close, wide target and with a distant, narrow one, in Fitts’s experiments (1954).

Solid evidence. The law describes the act of pointing. It does not measure how long we take to decide where to point.

1954
Paul M. Fitts
Measured how the time of a movement changes with the distance and size of the target.
1983
Stuart K. Card, Thomas P. Moran and Allen Newell
Built the law into models for predicting interface use.

Fitts, P. M. (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47(6), 381–391. View source: Fitts, P. M. (1954)
Card, S. K., Moran, T. P., & Newell, A. (1983). The psychology of human-computer interaction. Lawrence Erlbaum Associates.

Last reviewed: October 25, 2026