Square Footage Calculator
Add up the area of one or more rooms in different shapes to get total square footage, the number nearly every other estimate starts from.
Add a room, pick its shape, and enter the dimensions in feet. Add as many rooms as you need and the total updates when you calculate. Use this first, then carry the square footage into the flooring, paint, insulation, or roofing tools.
Areas are computed per room and summed. Circle area uses the radius, which is half the diameter.