Convert area and depth into cubic yards
For a rectangular area, multiply length in feet by width in feet to get square feet. Convert depth from inches to feet by dividing by 12. Multiply area by depth in feet, then divide by 27 to convert cubic feet to cubic yards.
For example, 1,000 square feet at 4 inches deep is 1,000 × (4 ÷ 12) ÷ 27, or approximately 12.35 cubic yards before an allowance. Keep the full precision during the calculation; round only the displayed result and the final order quantity.
- Cubic yards = square feet × (depth in inches ÷ 12) ÷ 27.
- For irregular shapes, calculate sections separately and add their volumes.
- Check measurement units before multiplying; inches and feet are not interchangeable.
Use the selected material's density
Multiply cubic yards by tons per cubic yard to estimate loose tons. A planning density of 1.55 tons per cubic yard for a limestone base gives about 19.14 tons for the example above, before an allowance.
These are planning estimates, not scale-ticket guarantees. Source gradation, moisture and compaction affect actual weight and installed volume. Light mulch and compost need a different density from dense stone or soil.
Apply allowance and minimums deliberately
With the calculator's optional 10% allowance, the example becomes about 21.05 estimated tons. Rounding up to whole tons gives 22 tons. The calculator also respects the selected material's planning minimum.
Do not add the same allowance twice, or mistake a waste toggle for a specified compaction factor. Discuss placement, irregularity and compaction with the installer. The planning result is not a recommendation to change an engineered layer thickness.
Truck count has both weight and volume limits
The NTM planning model uses a 16-ton tandem load. A 22-ton request therefore needs at least two planned loads, with the actual allocation confirmed by dispatch. A partial final load is different from rounding the purchase quantity to a full truck.
For light material, the model also checks an 18-cubic-yard bed-volume cap. A truck can run out of bed space before it reaches its weight limit. Actual equipment capacity, safe access and applicable load restrictions still control the delivery plan.
Some products should not use an area calculator
Precast blocks and selected landscape boulders are quoted by piece or confirmed weight and dimensions. Applying a generic tons-per-yard value to them would produce a misleading purchase quantity.
For those items, provide a piece count, size requirements, lifting plan and delivery constraints. For bulk grades, use the material-specific calculator and carry the selected material into the quote request so dispatch can review the same assumptions.