Construction & DIY Calculators
3 free calculators · runs in your browser · nothing you type is stored
Buying too little means a second trip and a mismatched batch; buying too much is money in the garage. These calculators work out the quantity from your measurements, add an allowance for waste, and round up to what you can actually buy — boxes of tiles, litres of paint, bags of concrete.
They assume a straightforward job. Awkward cuts, uneven surfaces and absorbent substrates all push the real figure up, so keep the spare allowance and check the coverage printed on the product you choose.
All Construction & DIY calculators
Tile CalculatorWork out how many floor tiles and boxes to buy, with a waste allowance, rounded up.Paint CalculatorEstimate litres or gallons of paint for a room from wall sizes, openings, coats and coverage.Concrete CalculatorFind the volume of concrete for a slab, footing or column in m³, ft³ and yd³, with bags if you want them.
Which calculator do I need?
Start from the job you are trying to do.