Home & Construction
Calculators for planning a home project before you buy materials.
Start with Square Footage Calculator to measure the space; it adds up rectangles, triangles, and circles. Paint Calculator turns wall area, minus doors and windows, into gallons for the number of coats you plan. Flooring Calculator adds a cutting-waste allowance and converts the total into boxes using the coverage on the label, and Concrete Calculator gives a slab’s volume in cubic yards and the number of 80, 60, or 40 lb bags. BTU Calculator sizes a room air conditioner from the ENERGY STAR table and its adjustments for sun, occupants, and kitchens.
All home and construction calculators
Square Footage Calculator
Add up the square footage of any space — rectangles, triangles, and circles per area, summed live with the metric equivalent shown.
Paint Calculator
Work out how many gallons of paint a room needs — wall area minus doors and windows, times coats, at your can's real coverage rate. Math shown.
Flooring Calculator
Work out how many boxes of flooring to order — area plus the right cutting-waste allowance for your layout, divided by the coverage on the box label.
Concrete Calculator
Slab volume in cubic yards plus exact 80/60/40 lb bag counts from the yields printed on the bags — with an honest bags-vs-ready-mix threshold.
BTU Calculator
Size a room air conditioner with the ENERGY STAR table and its published adjustments — sun, occupants, ceilings, kitchens — plus why oversizing backfires.