Gravel Base Depth Calculator
Calculate the gravel for a compacted base in cubic yards and tons from the area and how deep you want the base.
How it works
cubic feet = length × width × (depth ÷ 12) · cubic yards = cubic feet ÷ 27 · tons ≈ cubic yards × 1.4
A gravel base is a shallow slab of stone: area times depth gives cubic feet, divided by 27 for cubic yards. Suppliers often sell by the ton, and crushed gravel weighs roughly 1.4 tons per cubic yard, so the volume is converted for ordering. Because gravel compacts, buy for the finished depth and expect to spread a bit more loose material than the final measurement suggests.
Worked example
A 20 × 12 ft pad at 4 in: 20 × 12 × (4 ÷ 12) = 80 cu ft, ÷ 27 = 2.96 cubic yards. At about 1.4 tons per yard that is 4.15 tons; at $45 per ton, roughly $187.
Frequently asked questions
How deep should a gravel base be?
Four inches suits patios and walkways; driveways want 6–8 inches or more over soft or clay soils. Deeper bases spread the load and drain better, which is what prevents settling and frost damage.
How many tons is a cubic yard of gravel?
About 1.4 tons for typical crushed stone, though it ranges roughly 1.3–1.5 depending on the rock and moisture. Ask your supplier for the exact conversion of the product you are buying.
Should I account for compaction?
Yes — gravel settles 10–20% when compacted, so spreading and tamping in lifts uses a little more loose stone than the finished depth implies. Ordering to the compacted depth plus a small margin covers it.
Related calculators
Estimates only — add for waste and confirm against local building codes and supplier specs.