Methodology and sources
How YardageHQ calculators work, and where their numbers come from.
How the calculators are built
Each calculator runs entirely in your browser; nothing you type is sent anywhere. Results are rounded only for display, and every page shows the formula it uses and a worked example you can check by hand.
The cubic yard behind every calculator
Concrete, mulch, gravel and asphalt are all sold by volume or by weight, so most YardageHQ calculators start the same way: length × width × depth gives cubic feet, and dividing by 27 gives cubic yards. From there each calculator converts to what you actually buy: bags from the manufacturer’s stated yield, tons from a density you can edit, or bundles from the shingle maker’s coverage.
Where a figure depends on a product or a supplier (bag yield, stone density, asphalt density, salt target), the page names its source and lets you change the number.
By calculator
| Calculator | Based on | Last checked |
|---|---|---|
| Concrete calculator | QUIKRETE Concrete Mix (No. 1101) data sheet | October 28, 2026 |
| Asphalt calculator | Minnesota Asphalt Pavement Association asphalt calculator | October 28, 2026 |
| Square footage calculator | NIST Guide to the SI, Appendix B.9 conversion factors | October 28, 2026 |
| Mulch calculator | University of Florida IFAS Extension, Florida-Friendly Landscaping: Principle 4, Mulch | October 28, 2026 |
| Gravel calculator | Vertigraph gravel and aggregate calculator, Gravelshop: Drainage Gravel #57 calculator | October 28, 2026 |
| Deck calculator | 2025 California Residential Code, Section R507 Exterior Decks (Table R507.7) | October 28, 2026 |
| Roofing calculator | GAF: How many bundles of shingles are in a square | October 28, 2026 |
| Pool salt calculator | Hayward AquaRite owner’s manual, NIST Guide to the SI, Appendix B.9 conversion factors | October 28, 2026 |
Corrections
If you find an error, tell us and it will be checked and fixed.