Gravel is sold by the ton, but the math starts with volume — and because stone weighs different amounts, the density of your gravel matters.
Step 1 — volume in cubic yards
Same identity as mulch: one cubic yard covers 324 ft² at 1 inch.
cubic yards = area (ft²) × depth (in) ÷ 324A 100 ft² area at 4 inches is 100 × 4 ÷ 324 = 1.23 cubic yards.
Step 2 — cubic yards to tons
Multiply by the stone’s density in tons per cubic yard:
| Material | Density (tons/yd³) |
|---|---|
| Crushed stone (generic) | 1.4 |
| Crushed gravel (¼–2 in) | 1.5 |
| Crusher run / road base | 1.6 |
| Large rock (2–6 in) | 1.25 |
Using the generic 1.4: 1.23 × 1.4 = 1.7 tons. Density really does vary by
stone type, gradation, and moisture, so pick the closest match — and when in
doubt, 1.4 is the safe planning figure (some calculators use 1.5 and over-order
by ~7%).
Add a compaction allowance
Gravel settles and compacts, and some is lost to uneven ground, so add about 10%. Our example becomes ~1.9 tons; since stone is sold by the half-ton, order 2 tons.
How deep, and how much does a ton cover?
- Driveway surface: ~4 inches (6–8 inches total over a compacted base for a new driveway).
- Coverage: about 100 ft² per ton at 2 inches of typical crushed stone. Coverage halves as you double the depth.
Worked examples (4-inch depth, 1.4 tons/yd³)
| Area | Cubic yards | Tons (+10%) |
|---|---|---|
| 100 ft² | 1.23 yd³ | 2.0 |
| 200 ft² | 2.47 yd³ | 4.0 |
| 500 ft² | 6.17 yd³ | 10.0 |
Frequently asked questions
How many tons of gravel do I need for a driveway? Multiply area × depth ÷ 324 for cubic yards, then × ~1.4 for crushed stone, then add ~10%. A 10 × 50 ft driveway at 4 inches is about 6.2 yards ≈ 10 tons.
How much area does a ton of gravel cover? Roughly 100 ft² at 2 inches deep, or ~80 ft² at 2.5 inches, for typical crushed stone.
What’s the cheapest gravel for a driveway? Crusher run (a stone-and-fines mix that compacts hard) and #57 crushed stone are the usual budget choices; delivery is often the biggest line item.
Get density-aware cubic yards and tons for your project with the Gravel Calculator.