Geometry and exact conversions
Rectangle area = length × width. Circle area = π × (diameter ÷ 2)². Volume = area × depth. We use 12 inches per foot, 27 cubic feet per cubic yard, 0.3048 meters per foot, and 0.764554857984 cubic meters per cubic yard.
Allowance
We sum measured volumes first, then multiply by 1 + allowance ÷ 100. The default 5% is an editable planning assumption. It is not a universal waste or compaction specification. Set it to 0% for measured volume only.
Weight and bags
Estimated gravel weight in US short tons = order volume in cubic yards × density in US tons per cubic yard. The 1.4 starting density is illustrative, not a sourced specification for every aggregate. Whole mulch bags = ceiling(order volume in cubic feet ÷ bag volume in cubic feet).
Price and rounding
Material cost uses unrounded volume or weight, or the whole bag count, multiplied by the price you enter. Results display up to three decimal places for cubic yards and two for most other values. Extremely small values may display as zero after rounding; these tools are intended for landscaping quantities. Currency is USD. Supplier order increments, taxes, delivery and labor are not included.
Checks and limitations
The calculation engine is tested against exact conversions, multiple areas, circular geometry, bag rounding, allowances and invalid values. Measurements and material density still determine real-world accuracy. Shape simplification and ground variation can create differences between this estimate and the actual order.