Using Calculators for User Engagement

Calculators can play important roles on websites. They are especially popular for financial sites, where they can help users calculate mortgage payments, retirement needs, interest earned, and so on. They also appear on other sites, where users can calculate things as varied as their BMI (body mass index), carbon footprint, life expectancy, or gas mileage.

Zhou, Yun and Cliff Anderson. Usability Professionals Association (2008). Articles>Usability>Assessment>User Centered Design