ProjectQty separates geometry from ordering assumptions. The calculator first finds a base quantity from the dimensions you enter, then applies waste, density, package yield, and price only where those values are relevant and visible.
1. Geometry and units
Rectangular volume is length × width × depth. Circular volume is π × radius² × depth. All measurements are normalized before totals are added. One cubic yard is exactly 27 cubic feet. Metric conversions follow NIST conversion factors.
2. Waste and order rounding
Waste is applied after base areas are summed. Cubic volume stays decimal. Whole products—such as bags and pavers—round up only at the final order unit because a fraction of a packaged unit cannot normally be purchased.
3. Material density
Loose-material weight is an estimate: density changes with material gradation, moisture, voids, and compaction. ProjectQty displays its planning density and lets you replace it with a supplier value. When no defensible default exists, the correct result is volume only—not invented tonnage.
4. Packaged-product yield
Bag counts use stated or conventional product yield and always round up. Packaging and yield differ by manufacturer and product line, so the current bag label or technical data sheet remains the final authority.
5. Pricing model
Quantity calculations never depend on a live price. You can enter a local per-bag, per-ton, or per-cubic-yard price from your own quote. ProjectQty V1 does not scrape retailer prices, claim national prices are local, or label cached data as real time.
Calculate quantity → confirm product specification → request a current delivered quote → update the price input → print the supplier list.
6. Validation and limits
Negative values are rejected and pause the estimate. Waste is limited to 0–50% and identical-area quantity to 1–999. The tools are planning aids, not engineering, architectural, code, safety, or purchasing approvals.
7. Reproducible validation
ProjectQty publishes first-party reproducible checks, not independent reviews. Each case shows exact inputs, formula steps, intermediate values, rounding, expected results, and the boundary that still needs supplier or professional verification.