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Whether you're constructing a box or designing a house, there is no way around making calculations. You could use a standard calculator or expensive graphing calculator, but none of these have the formulas you use for construction on a regular basis. The Calculated Industries Construction Master 5 has almost everything you would need on the jobsite for easy calculations. It has unit converters so you can jump from Standard United States units like feet and inches and jump to the metric system without having to work any of those out on paper. This function works for distances, volumes, and areas. There is a wide variety of dedicated functions found on this calculator, from figuring out stairs to rafters to different circles and rake walls. It also has the Pythagorean Theorem built in for you to work with right triangles for certain windows or trims.