What this is
Eight calculators for the materials a job actually orders: concrete, gravel, mulch, asphalt, topsoil, sand, rebar, and a plain cubic-yard converter for anything else. Each one works out the quantity from your measurements, applies the waste or compaction allowance the material needs, and writes the result up as a delivery ticket you can print or save.
It is built for the person standing in the yard with a tape measure — a homeowner doing one patio, or a small crew doing one a week — who needs the number, the bag count and a rough cost before they call the supplier.
What the numbers are and are not
The arithmetic is the arithmetic: length by width by depth, divided into cubic yards, multiplied by a density. The densities and prices on each page are placeholders in a typical range, and the page says so next to every one. Type in the figure your supplier quotes and the ticket recalculates.
The result is an estimate for ordering material. It is not an engineering design, it does not choose a mix or a bar size for you, and it leaves out delivery, minimum-order charges, taxes and labour, which the printed sheet says in as many words.
Independence
Bulk Math is not a supplier and does not sell material. No manufacturer or landscape yard pays for a place on these pages, and the defaults are not anyone’s product. The site is supported by advertising, which is labelled as such.
Saved projects
Anything you save stays in your own browser. There is no account, nothing is uploaded, and the site cannot see your estimates. The privacy page spells out exactly what is and is not collected.
Corrections
If a number looks wrong, it may be. Send the page, what you typed and what you expected to the contact address; a real mistake in the arithmetic gets fixed and noted.