How Understanding Fitts’ Law Takes Will Take Your Usability to the Next Level

Fitts’ Law was developed in 1954 by one psychologist called Paul Fitts. The law explained the interaction between human beings, ergonomics and computers. Fitts’ Law was used in determining or predicting the time that it will take an individual in moving rapidly to the target area (object area). This is usually determined by factoring the distance the target is from you and the size of the target. In summary, the law states that the bigger the object is and the closer it is to a person, the easier then it is to move this object and vice versa.

What does Fitts’ Law include in terms of variables?

The law is centered on an equation which relates to time, distance and width. The law is used in illustrating how long it takes to reach a particular target. In this equation, time refers to the amount of time that is required to complete the whole movement. Distance refers to the distance between the start point and the end point (the targeted object) and the width of the targeted object, width. The law in it is original form is applied in single dimensional movements (not in more than one dimension or two dimension), it is used in describing simple motor responses and finally the law describes untrained movements (not those movements where one has been trained for long)

Understanding Improves Usability in the Following Ways:

Interface designing which may include coming up with appropriate widgets for use such as popup menus. This will help in saving time considerably which will go a long way in being even more productive (resourceful) and effectiveness of an individuals or staff if it is in an organization.

Decreasing the amplitude of movement will help in decreasing the time required in a getting a fixed sized target. It is therefore important to decrease the distance that one moves before getting to his/her target as this will help in increasing performance. For those involved in designing, this is an important factor to consider as it will most definitely increase usability of computers in the manner in which they interact with human beings.

Clickable area in websites; if the law is taken into consideration, then the clickable area in most websites will be increased. This will make use of these websites easier to manipulate through as compared to those where the clickable area is very small. This will by far make it easier for people to navigate through your website unlike if the law was not applied. Utilize all the available pixel space as this will increase clickable area thus making it easy to use as less time will be used in reaching the targeted object. Smaller clickable areas make it hard to navigate through a website quickly.

Fitts’ Law therefore is a model which can be beneficial to designers in making informed decisions in various user interfaces and web layouts. The law can be used with other existing laws in coming up with user interface items in a proper order. Fitts’ Law will most definitely make work easier to an individual or an organization if applied appropriately hence improved performance.


Jessica is the Lead Author & Editor of UsabilityLab Blog. Jessica writes for the UsabilityLab blog to create a source for news and discussion about some of the issues, challenges, news, and ideas relating to usability.