Every other calculator gives you a number you can't take to a shop. Nobody sells 14.6 litres of paint, 1.32 cubic metres of concrete or 34.7 square metres of turf — they sell tins, truckloads and pallets. These work out what you actually put in the trolley, what's left over, and when the honest answer is to buy less.
Bake prices into a calculator and it's out of date within months. Worse, the sums stop making sense: a 10 litre tin is often the same price as two 4 litre tins, and a bulk load can cost less than half as many bags — which flips the answer entirely. Only your supplier knows today's price.
So we don't quote prices. We accept them. Type in what you were quoted and we'll total it, work out the cost per square metre, and find the exact point where bulk delivery overtakes bags for your supplier. That answer can't go stale, because it's built from your numbers on the day.
Free, no login, no email. These calculators are funded by the advertising on the page and nothing else — no affiliate links, no lead generation, no data sold. That matters, because a tool paid for by the people selling you the materials can never tell you to buy fewer of them.
Coverage figures, densities and bag yields are trade-typical and deliberately cautious, so you don't run short. Where your product states its own figure, use theirs — every calculator lets you override ours. See every figure we use, and where it came from, or tell us if one is wrong.