How the calculator works
Two steps: volume, then weight. Cubic yards = area × (depth ÷ 12) ÷ 27, then multiplied by the material's density in tons per cubic yard. Density is why the material dropdown matters. A yard of lava rock weighs half what a yard of limestone does, and suppliers sell most stone by the ton.
Worked example: a 400 sq ft gravel path at 3″ deep is 100 cu ft = 3.7 yd³. In crushed gravel (1.4 t/yd³) that's 5.2 tons; in lava rock it would be only 2.8 tons.
Choosing the right stone
- Crushed gravel / road base: angular with fines, locks tight when compacted, the choice for driveways and base layers.
- Pea gravel: rounded and comfortable underfoot, but migrates; needs edging.
- River rock: decorative beds and drainage swales; too round to compact.
- Decomposed granite: compacts to a firm natural-looking path surface.
- #57 limestone: the workhorse ¾″ drainage and driveway topping stone.
Depth guidance
- Decorative ground cover over fabric: 2–3″
- Walking paths: 3″ over a compacted base
- Driveways: 4″ base lift + 4″ middle + 2–3″ topping, built in separate compacted lifts, not one pour