About Home Calc Box

Home Calc Box helps homeowners and DIYers work out how much material a project needs before they buy it: concrete for a slab, pavers for a patio, boards for a deck, paint for a room, shingles for a roof.

How we calculate

• Volumes and areas use the standard geometry shown on each page, so you can check the math yourself.
• Bag yields, coverage rates and weights are typical manufacturer and industry figures (for example, an 80 lb bag of concrete mix makes about 0.60 cubic feet, and a gallon of paint covers about 350 square feet). Check the label on the product you buy.
• Prices are rough US retail averages for planning. Local prices vary a lot, so every calculator lets you enter your own.

Our numbers are estimates for planning and buying materials. They are not engineering advice: follow local building codes and product instructions, and use a professional for structural work.

Spotted a mistake? Let us know.