Formula
Depth in inches becomes feet, then the volume is weighed and divided into short tons:
tons = length × width × depth / 12 × 105 / 2000
105 pounds per cubic foot is a planning density for loose crushed gravel. Sand uses 100, and mulch is sold by the cubic yard instead of weight.
Assumptions
- The area is a rectangle.
- The gravel is loose, not compacted.
- A ton is the 2,000-pound short ton.
Worked example
A 10 by 20 foot area at 4 inches of gravel weighs 3.5 t.
Input definitions
- Planning density
- 105 pounds per cubic foot, about 1.4 short tons per cubic yard.
Limitations
Moisture and compaction change the delivered weight. The pit's ticket is the weight you pay for.
Questions
Why 105?
It is a common loose weight for crushed gravel, between a lighter dry sand and a heavier solid stone.
Is a metric tonne used?
No. The ton on this page is 2,000 pounds.