GravelMatter is a small, independent set of calculators for one job: working out how much gravel, stone or rock to order.
What it does
It turns measurements into a quantity you can take to a supplier — cubic yards or metres, US tons or tonnes, bags — and shows its working. The tools share one calculation engine, so a cubic yard is calculated the same way on every page.
What it doesn't do
It doesn't sell materials, take referral fees from suppliers, or claim to know your local stone. Densities are general published values; your supplier's figures are better, and every calculator lets you use them. It is not engineering advice.
How it's built
The site is static HTML with a small amount of JavaScript for the calculators. There are no accounts and no analytics of our own; advertising is served by Google AdSense (see the privacy policy). The calculation engine has automated regression tests, described on the methodology page with every formula and source.
Funding
The site is funded by advertising through Google AdSense. Advertising does not affect how results are calculated, and we don't sell materials or take supplier referral fees.
Who it's for
Homeowners and DIY builders planning a path, patio, bed or driveway; landscapers and contractors who want a quick, transparent check of a quantity before quoting or ordering. Everything works in imperial and metric.
How the content is produced
The calculators, worked examples and guides are written around one tested calculation engine. Every number in an example or table is generated from that engine when the site is built, so the explanations can't drift from what the calculators actually do. Density figures come from published sources listed on the methodology page; where no reliable product-specific figure exists, we say so instead of inventing one.
How it's maintained
Each change to a formula, default value or source is recorded in the revision history. Pages show the date they were last reviewed. We don't publish prices, supplier rankings or reviews.
Corrections
If you find an error — a formula, a conversion, a source — please get in touch. Corrections are made promptly and the page's review date is updated.