The problems that most businesses face when headed for web design/development is that of scope creep. As projects are kicked off and delivered, the agreed-upon requirements and deliverables keep changing, primarily due to the lack of initial vision on the part of businesses that are venturing into getting their first website made. 

A calculator like this one helps you determine the major scope, requirements, and expectations right in the initial phase. This not only helps businesses determine the website design cost but also manages the expense and the scope of the project in the long run.