Home calculators

Square footage, concrete, paint, roofing and other project materials, plus running costs.

Each with the formula, a worked example and sources.

• BTU Calculator for Room Air ConditionersThe air conditioner size (BTU) for a room, using ENERGY STAR sizing guidance.
• Concrete CalculatorCubic yards and premix bags for a slab, footing or round column.
• Electricity Cost CalculatorWhat an appliance costs to run per day, month and year, and its kWh.
• Gravel CalculatorCubic yards, tons and bags of gravel, stone, sand, topsoil or mulch.
• Paint CalculatorGallons of paint for a room's walls and ceiling, net of doors and windows.
• Roofing CalculatorRoof area, roofing squares and shingle bundles from the footprint and pitch.
• Square Footage CalculatorSquare feet, square yards and square meters for any room or space.
• Tile CalculatorTiles and boxes for a floor or wall, with grout joints and waste.