About ShovelMath
ShovelMath is a free collection of calculators that turn real-world project measurements into the units suppliers actually sell: cubic yards, tons, bags, rolls and pallets.
Why this site exists
Ordering bulk material is one of the most error-prone parts of any DIY project. Suppliers quote by the cubic yard or ton; your project is measured in feet and inches. Order too little and you pay a second delivery fee — order too much and you're stuck with a pile of gravel on the driveway. Every calculator on this site does one conversion well, shows the formula behind it, and explains the assumptions so you can double-check the math yourself.
How the calculations work
Volume calculators use the standard formula Length × Width × Depth ÷ 27 = cubic yards, then convert to weight using typical material densities (for example, crushed gravel at about 105 lb per cubic foot, topsoil at about 75 lb, wood mulch at about 22 lb). Densities vary by source, moisture and compaction, so every result should be treated as a planning estimate — we say so on every page, and we recommend confirming final quantities with your supplier.
Where the industry has a standard practice — like a 4-inch compacted gravel base under pavers, 2 bags of concrete per fence post, or a 5–10% waste allowance — the calculators build it in and label it clearly.
Our principles
- Free, forever. No signup, no paywalls.
- Private. All calculations run in your browser. Nothing you type is sent to a server or stored.
- Transparent. Every calculator shows its formula and reference tables, so you never have to trust a black box.
Contact
Found an error in a formula or density value, or want to suggest a calculator? We take accuracy seriously and review every report. Reach the site maintainers via the feedback address listed in our Privacy Policy page's footer domain registration, or check back soon — a contact form is on the roadmap.