What this site is
The DIY Calculator is a set of calculators for the materials of a home project: gravel, mulch and soil today, with concrete, stairs, drywall, fences and roofing to follow. Each one takes the measurements you have and answers in the units a store or a supplier sells: bags, cubic yards, tons.
It is an independent site. No retailer or manufacturer owns it, and none pays to be named on it.
How we work
- Geometry and published figures. An answer is area times depth, and a weight or a bag size that somebody published. Nothing is estimated from experience we do not have.
- Every default has a source. Densities, bag sizes and depths each name where they come from and the day we last read them there. How we calculate lists them all.
- Every default can be changed. Your supplier knows their stone better than a table does. Type their figure in, and the answer follows it.
- The working is shown. Each result opens on its formula, with your numbers in it.
- Checked against worked examples. The engines are tested on examples computed by hand before a page is published, and the examples you read in each article are computed by the same engine as the calculator beside them.
What we do not do
We do not size anything that carries a load: no beam or joist spans, no footings, no slab thickness. We give no verdict on building codes, and we sell no leads to contractors. For those questions the right answer comes from your plans, your building department or an engineer.
Mistakes
A calculator that is wrong is worse than none. If a number looks off, tell us, with the link to the page as you had it: the address carries your inputs, so we see exactly what you saw.
Updated . How we calculate. Found a mistake? Tell us.