Gravel Calculator
Enter the area and depth to get cubic yards, tonnage for the selected material (gravel, crushed stone, sand, topsoil, mulch), bag count, and the 10% order margin.
Last updated: 2026-09-22
How the calculation works
- Volume is the simple L × W × depth, converted to cubic yards — the unit landscape suppliers sell by.
- Weight converts from volume with the material's loose density: crushed stone packs heaviest at ~1.6 t/yd³, mulch lightest at ~0.4.
- The order figure adds 10% because real subgrades are never perfectly flat and loose aggregate settles 10–15% once compacted or walked on.
- The bag count (0.5 ft³ bags) prices the retail option for small areas where delivery minimums dominate cost.
Formula
V_ft³ = L × W × (depth/12) V_yd³ = V_ft³ / 27 tons = V_yd³ × density(material) order = tons × 1.1
| Symbol | Meaning | Unit |
|---|---|---|
V | Volume to fill | ft³ → yd³ |
ρ | Loose delivered density by material | tons/yd³ |
1.1 | Margin for uneven subgrade and settling | — |
Worked example
Interpreting the result
Suppliers sell loose aggregate by the ton and quote minimum loads (often 3–5 tons for delivery). The margin matters in both directions: short and the second truck carries a delivery minimum; long and you own a pile. Compaction changes the math for driveways — crushed stone compacted in lifts loses 10–15% of its loose depth, so a 4 in compacted base needs ~4.5–5 in loose, which is exactly the margin included here. Densities vary by quarry and moisture; the figures here are typical delivered values, not guarantees.
Assumptions
- Flat area, loose-delivered material at typical moisture.
- Densities: gravel 1.4, crushed stone 1.6, sand 1.5, topsoil 1.0, mulch 0.4 tons per yd³.
- No existing base material or geotextile accounted.
Limitations
- Compacted vs loose: the tonnage is the same but the covered depth shrinks 10–15% after compaction.
- Wet sand and gravel weigh 5–10% more than typical figures.
- Irregular areas (circular beds, trench runs) need area computed separately.
Loose, compacted and the settling surprise
Aggregate is delivered loose and ends up compacted, and the 10–15% volume loss between those states is where first-time estimators get burned. A trench filled level with loose gravel today will sit a half-inch low after the first rain or plate compactor pass. The professional habit is to order by compacted depth but measure loose: target depth × 1.12 for crushed stone, × 1.15 for sand. For driveways this also matters structurally — the base is supposed to be compacted in 2–3 in lifts, and a single 6 in loose lift will never compact uniformly through its thickness. The tonnage doesn't change with compaction; only the depth it settles to does.
Frequently asked questions
How many tons of gravel per cubic yard?
About 1.4 tons per yd³ for pea gravel and river rock, 1.5–1.6 for crushed stone and 1.5 for sand. Mulch is much lighter at ~0.4 t/yd³ — which is why mulch deliveries look enormous for the same weight.
How deep should gravel be for a driveway?
4–6 in of compacted crushed stone for cars; 6–8 in for trucks or soft subgrade, laid in two lifts. At 4 in over a 10 × 20 ft driveway, that's about 2.5 yd³ ≈ 4 tons.
How much does a 0.5 cubic foot bag of gravel cover?
At 2 in deep, one 0.5 ft³ bag covers 3 ft². A 100 ft² bed at 2 in needs about 34 bags — the point where a loose delivery at a third of the price wins.