Home Project Calculators
Work out how much concrete, gravel, mulch, paint or tile your project needs — and how many bags, yards or boxes to actually buy.
Every calculator here answers the question you will actually be asked at the counter, which is not how many cubic yards your patio comes to but how many bags that is. A slab needing 1.78 cubic yards is 88 bags of eighty-pound mix, or two yards ordered ready-mixed, and those are different purchases with different prices and different amounts of work. Where a waste allowance belongs, it is a field you can see and change rather than a percentage baked into the answer, and where one does not — paint, gravel, or a bare area — the page says why. Every quantity rounds up, because being one bag short stops a pour while a spare bag costs a few dollars. Start with the square footage calculator if you are measuring a room or a patio, then take that area to whichever material you are buying.
- Square Footage Calculator
Work out the square footage of a room, patio or garden bed, and get the same area in square yards and square inches for whatever you are buying.
- Concrete Calculator
Work out how much concrete a slab, footing or column needs, and how many 80, 60 or 40 pound bags that is — or whether to order it ready-mixed instead.
- Gravel Calculator
Work out how much gravel, sand or topsoil a driveway or path needs, in cubic yards and in tons — because aggregate is sold by weight, not volume.
- Mulch Calculator
Work out how much mulch a bed needs in cubic feet and yards, how many two or three cubic foot bags that is, and when bulk delivery is cheaper.
- Paint Calculator
Work out how many gallons of paint a room needs, allowing for doors, windows and the number of coats, with the quart figure so you buy closer to what you need.
- Tile Calculator
Work out how many tiles and how many boxes a floor or wall needs, allowing for cuts, with the spare tiles counted so you keep a batch-matched reserve.
Questions
- Why do these tools tell me bags rather than cubic yards?
- Because bags are what you buy. Cubic yards are what the arithmetic produces, and every calculator on the internet will give you that. The number you need standing in the aisle is how many to put in the trolley, and that depends on the bag size, which is why we ask.
- How much waste should I allow?
- Concrete and mulch default to ten percent, applied to the bag count, covering uneven ground, spillage and the bit that never quite comes out of the barrow. Tile wants more — ten laid straight, fifteen for a diagonal or herringbone layout, because almost every edge tile there is a cut. Paint needs none — the coverage figure on the tin already assumes normal application, so a percentage on top would buy you a tin you never open. Gravel needs none either, for a different reason — aggregate has no bag to pad, and the order already rounds up to a whole cubic yard, a margin bigger than any percentage would add. Square footage has no material, so it does not ask.
- Do you show prices?
- No, deliberately. Material prices vary by region, by supplier and by week, and a national average would be confidently wrong for most people reading it. We would rather tell you exactly what to buy and let you price it where you are buying it.