About

MaterialMath exists because most material calculators stop one step short of the thing you actually need. They tell you how many cubic yards of concrete a slab takes and leave you standing in a builders' merchant working out how many bags that is.

Every calculator here finishes the job. You get the quantity in trade units, the number of bags or boxes or sheets to put in the trolley, a waste allowance that reflects how that particular material is actually lost, and a cost if you tell it what you are paying. Then you get a shopping list you can copy.

It is built for DIYers and contractors, mostly working from a phone, often outdoors, usually mid-job. That shapes everything: the answer has to be readable in daylight, reachable without scrolling, and shareable as a link that reproduces exactly what you saw.

The site is free and supported by advertising. It does not sell materials, take affiliate commission on suppliers, or have any reason to tell you to buy more than you need.

Who builds it

Team MaterialMath — a small independent group, and the byline on every page here. We have chosen not to publish an individual's name and qualifications, and there is no point being coy about the trade-off: a named expert whose background you can look up is a stronger reason to trust a figure than a team name is.

So we have tried to earn it a different way. Not one physical constant on this site was decided by us. Densities, bag yields, coverage rates and waste factors come from manufacturer data sheets and published standards, each one cited on the page that uses it with a link to the document — so the question is never whether to take our word for it, because our word is not what any of it rests on. Where a figure could not be sourced, the tool says so and declines rather than estimating.

Every page carries the date it was published and the date it was last checked, both from the version history rather than from a clock. When a figure turns out to be wrong we correct it and leave a note on the page saying what changed. The methodology page sets out the whole of it: where the constants come from, how rounding and waste are decided, what the test suite checks, and what these calculators will not do.

If you think a number here is wrong, tell us, and bring the source you are working from. A citation we can check is worth more to us than a correction we cannot.