groundmath

Methodology

groundmath.com publishes material-quantity calculators for landscaping and sitework, each showing its formula and tracing its figures to a publication you can open. This page explains who runs the site, which sources may supply a number, how the data is versioned, and how to get an error fixed.

Who runs this site

groundmath.com is built and maintained by Cloudwards e.K. (owner: Oliver Sinz), a registered sole proprietorship in Kempten, Germany, which also runs the real-estate calculator site dealyield.app. Trading address, register entry and contact details are in the legal notice. The site is written for a US audience in US units, and every source behind it is American.

Where the numbers come from

Every density, coverage rate, depth, waste factor, bond correction and package size a calculator uses is cited to a publication anyone can open. Sources are accepted in a deliberate order.

  • University extension services first. Purdue, Penn State, Colorado State, Utah State, Oregon State, Maryland, Nevada Reno, Iowa State, Cornell and others publish free, regionally tested guidance for the person doing the work, and they name their assumptions.
  • Then government and federal references. State transport departments for aggregate conversions and earthwork allowances, the USDA Natural Resources Conservation Service for surfacing standards, the Consumer Product Safety Commission for playground depth, a city building department where a rule needs stating plainly, NIST for the unit definitions.
  • Then standards bodies and industry technical documents. The Brick Industry Association's estimating tables and the National Concrete Masonry Association's installation guide are what those trades work from.

Three kinds of source are not acceptable, whatever they rank for. Retailer marketing pages publish coverage charts written to move a pallet size, with no method behind them. Aggregator blogs repeat whatever the last one said; a number with no origin is not a number. And other calculators are not sources — copying a competitor's tons-per-yard factor imports an assumption nobody can trace.

groundmath currently uses US customary units and US-based material data and sources unless a page states otherwise.

Ranges, defaults, and why we do not average

Material properties are ranges, not numbers: topsoil density moves with texture and moisture, pallet coverage is set by the producer, tons per cubic yard varies by quarry. Where a source publishes a range, we publish the range, state which value the calculator computes with, and let you override it. Averaging the ends into one figure would be a fabrication twice over: no publication says the midpoint, and the width of the range is the most useful thing you can know before ordering.

Corrections that differ in kind are kept apart. Cutting waste is added to the computed quantity as its own visible line. Compaction is a change in volume, applied in the direction the page's cited depth calls for — never both at once, never rolled into one fudge factor. Where nothing is published, nothing is applied: no settling allowance on a raised bed, no breakage allowance on brick, no compaction factor on rounded stone.

Versioning and freshness

The badge under each calculator's heading carries three markers, and they mean different things.

  • Formula v1.0 — the arithmetic the page performs. Bumped when a calculation step changes, so the same inputs would now produce a different answer.
  • Data v2026.1 — the release of the cited dataset the page reads: the year, then the release number within it. Every release has a changelog entry recording what changed and the exact quotes behind it. Bumped when a value changes, a material is added, or a correction lands.
  • verified Jul 31, 2026 — the day a person last opened that page's sources and confirmed they still read the same. It moves for that and nothing else: not for a rewrite of the wording, and never at build time. Values are re-verified at least annually, and at once when a report suggests a source has moved.

Where a badge stands over several materials — the homepage, the stone calculator — the date shown is the oldest of them, so it holds for every figure underneath.

What these calculators are not

Results are planning estimates for homeowners ordering material and contractors doing takeoffs — not engineering advice, and no substitute for your supplier's product specification, your drawings, or your local building code. Where those disagree with a page here, they win.

A qualified professional is required, not optional, where the question is structural or regulated: a retaining wall above roughly four feet, or any wall with fill, a slope or a surcharge behind it; a load-bearing base under a pavement; structural fill under a building or slab; a bed on a roof or deck, where the question is really load; and any work needing a permit. Pages carrying that risk say so at the top and again in the disclaimer.

Corrections

Found a number that looks wrong, a source that has moved, or a formula you disagree with? Email hello@groundmath.com with the page URL and, if you have it, the publication we should be reading instead. It is the address in the legal notice, and it reaches a person. Confirmed errors are fixed in the dataset, the changelog records the correction and its evidence, and the data version is bumped; the audit trail is never quietly erased. Where a source turns out not to support a claim, the claim is removed rather than softened.

Every calculator on this site

All 18, grouped by job, each with its own cited data table and source list.

Measuring and converting

Soil, compost and turf

Gravel, stone and sand

Walls and masonry

Fencing