How We Calculate

Every number on YardSizeCalculator comes from a stated formula — no black boxes. Here’s exactly how our calculators work, how we test them, and what our price estimates mean.

The formulas

Our calculators use standard volumetric and industry formulas. For example, material volume is always: volume (cubic feet) = length × width × depth (all in feet), then cubic yards = cubic feet ÷ 27. Bag counts, weights, and coverage rates follow the same transparent steps, shown on each calculator page under “How it works.”

Where project guidance exists (like compost application depths), we cross-check our rates against university extension publications — for example, our compost math matches Cornell University’s Compost Use Estimator. Each calculator page lists its own sources under “Sources & Methodology.”

How we test

  • Every calculator is run against real-world inputs — typical projects, unusual shapes, and edge cases (zero, negative, or missing values).
  • We test duplicate tools on the same page and unit switching (feet/inches/cm) so nothing breaks in real use.
  • Whenever a calculator’s code changes, it is re-tested in full before the update goes live. Last full verification of all 18 calculators: October 2026.
  • If a formula can’t be verified, the calculator doesn’t ship.

Local prices — how they work

Our cost estimates start from typical prices (for example, bulk compost at $25–$60 per cubic yard in the US). These are estimates for planning, not quotes. For an exact cost, enter your supplier’s actual price in the “Your Local Price” box — in your own currency (USD, GBP, EUR, PKR, INR, CAD, AUD, AED, SAR, CHF). We never convert currencies with made-up rates: if you don’t enter a price, you see our estimate; if you do, you see your exact cost.

Update policy

We re-verify every calculator whenever its code changes, and review price estimates periodically. Each page shows its last-updated date.

Disclaimer

All results are estimates for project planning, not professional advice. Material needs vary with soil conditions, compaction, and supplier practices — always confirm quantities with your supplier or contractor before ordering.