Free calculators for home improvement projects
Free, instant calculators for concrete, paint, mulch, gravel, drywall and tile. Work out exactly how much material to buy before you get to the store.
Every calculator here is free, needs no signup, and updates as you type. The maths is the same one contractors use — just without the guesswork about how much to buy.
Pick a calculator
Concrete CalculatorWork out how much concrete a slab needs in cubic yards and 40, 60 and 80 lb bags.Paint CalculatorFind out how many gallons of paint a room needs, accounting for doors, windows and number of coats.Mulch CalculatorCalculate mulch, soil or compost in cubic yards and 2 or 3 cubic foot bags for any garden bed.Gravel CalculatorWork out how much gravel, crushed stone or pea gravel a driveway or path needs, in cubic yards, tons and bags.Drywall CalculatorCalculate drywall sheets, joint compound and screws for any room.Tile CalculatorCalculate how many tiles and boxes you need for a floor or wall, including waste and thinset.
Why not just ask a chatbot?
You can, and you will get a number. The problem is you cannot see the formula, you cannot change one input and watch it respond, and you cannot check it twice and get the same answer. These are plain calculators: fixed formulas, live results, and a written explanation of where every number comes from.
How to use them
- Pick the material you are buying.
- Enter the dimensions of the area — length and width in feet, depth or thickness in inches.
- Read the headline figure, then check the detail rows for bag or box counts.
- Round up. Ordering slightly too much costs a few dollars; running short mid-job costs an afternoon.
Affiliate links help keep these tools free and ad-light.