1. How do you calculate Gravel Tonnage and Volume?
Calculating the amount of gravel or soil needed for a landscaping project requires three steps:
- Step 1: Find the Surface Area (Length × Width).
- Step 2: Find the Cubic Volume (Area × Depth). If measuring in feet, divide the cubic feet by 27 to get Cubic Yards.
- Step 3: Multiply the Volume by the Density of the material to find the final weight in Tons.
2. What is the standard density of Gravel?
Different materials weigh different amounts. A cubic yard of topsoil is much lighter than a cubic yard of solid rock. Standard reference densities used in construction are:
- Crushed Stone / Gravel: ~105 lb/ft³ (approx 1.4 tons per cubic yard)
- Pea Gravel: ~100 lb/ft³ (approx 1.35 tons per cubic yard)
- River Rock: ~110 lb/ft³ (approx 1.5 tons per cubic yard)
- Sand (Dry): ~100 lb/ft³ (approx 1.35 tons per cubic yard)
- Dirt / Topsoil: ~80 lb/ft³ (approx 1.1 tons per cubic yard)
3. Why do I need a Waste Margin?
When loose material is spread, it settles and compacts into the ground over time, reducing its overall height. Additionally, spreading is never perfectly even, and some material is lost in transport. A 10% margin is highly recommended to ensure adequate coverage depth after the material has fully settled.
4. Tons vs Metric Tonnes
If you are using the Imperial system, the calculator outputs Short Tons (2,000 lbs). If you are using the Metric system, the calculator outputs Metric Tonnes (1,000 kg). In the US, landscape supply yards sell material by the Short Ton or by the Cubic Yard.