One of the most important factors that may gauge the success of website design is its usability. Usability is generally defined as the level of ease that a particular tool or man-made object has when people begin to use it to achieve a certain goal. In the case of Web usability, it refers to the ease and clarity of which people interacts with a website or page.

Usability of a certain website would depend on how easy a user interacts with it. It can also be measured by how fast a user learns using the different operations associated with the website. Usability of a website may also be gauged by how efficient it can be in achieving a particular task for a user. Satisfaction provided by the use of a certain website may also be used as a measure of its usability.

Measuring web usability may not be as simple as many would think. It requires an extensive study as well as testing to deem a certain website as high in its usability rate. This is very important especially for a lot of website owners since a high usability rate usually results in better web traffic as well as more repeat online users or visitors. But what makes usability measures more challenging is that it cannot be done on a direct quantitative method.

A website can only be measured as to its usability through indirect means such as the number of complaints received from users as to how difficult a certain system is. Poor web traffic or a low number of online visitors may also be used as an indirect means of gauging web usability although such results may also depend on other factors. Such inputs should be evaluated as a whole and not individually to have a better understanding of a website's usability.

There are many factors to consider when it comes to gauging web usability. Usability experts usually try to take note of who the users are, what their capabilities are and what they can learn. Usability experts also consider user objectives as well as take the general background of a certain group of users especially during the testing or trial period. Other considerations include knowing the context in which the user is working as well as the distribution of effort between the machine or the program and the user.

In designing websites as well as other software applications, usability in now a recognized component that determines product success.  Usability has been counted among other attributes such as performance and stability in trying to come up with website designs and structures. And because of its growing importance, there are a number of consultancy firms now providing services to help website owners gauge web usability and offer suggestions to improve or enhance such an attribute.