How to use this calculator
Enter rectangular dimensions and depth, choose extra material allowance, and replace the sample density with your supplier’s bulk density in kg/m³.
The math behind it
Volume = length × width × depth × (1 + allowance ÷ 100) Mass (kg) = volume (m³) × density (kg/m³) Metric tonnes = kg ÷ 1,000; US short tons = kg ÷ 907.18474
A worked example
A 2 m × 5 m area filled 10 cm deep is 1 m³. At an entered density of 1,600 kg/m³ and no allowance, the estimate is 1,600 kg or 1.6 metric tonnes.
Assumptions & precision
Dimensions must be positive. Extra material allowance is a nonnegative percentage added once to geometric volume. Exact international foot = 0.3048 m; yard = 0.9144 m. Rectangular geometry only. Actual waste, settling, excavation and supplier increments vary. Unrounded intermediate values; results display up to 6 decimal places. Magnitudes above 10¹⁵ are rejected. The 1,600 kg/m³ default is an illustrative input, not a universal gravel density. Moisture, stone type and compaction change density.
A common question
Are metric tonnes and US tons the same?
No. A metric tonne is 1,000 kg; a US short ton is 2,000 pounds, or 907.18474 kg. Both estimates are labeled.