Gravel driveway calculator
A driveway isn't one depth of one stone — it's a compacted base of crusher run topped with a thinner surface layer. This calculator does both layers at once.
Result
Driveway gravel
The two-layer recipe
Gravel driveways fail when one stone is asked to do two jobs. The standard build on firm soil:
- Subgrade: strip topsoil, crown the subgrade (crown ≈ ½ in per foot of width), lay woven geotextile.
- Base — 4 to 6 inches compacted of crusher run (also sold as QP, Item 4, ABC, road base): crushed stone with fines that pack like concrete.
- Surface — 2 to 3 inches of #57 (¾ in clean) or a decorative topper that sheds water and looks finished.
Soft clay or heavy trucks? Go 6–8 in of base. Full details and cost per layer: gravel driveway thickness guide.
How many tons is that?
Formula (per layer)
yd³ = length × width × depth (in) ÷ 12 ÷ 27 · tons ≈ yd³ × 1.35 (base) / 1.4 (surface)
Example — 50 ft × 12 ft single lane: base 4 in + surface 2 in totals 6 in of stone: 600 ft² × 6/12 = 300 ft³ ≈ 14.6 tons (11.1 base + 3.5 surface). That's one 15-ton delivery — have the truck tailgate-gate spread it in two passes.
| Driveway | Base 4in + surf 2in | Base 6in + surf 3in |
|---|---|---|
| 10 × 40 ft (400 ft²) | ~9.7 t | ~14.6 t |
| 12 × 50 ft (600 ft²) | ~14.6 t | ~21.9 t |
| 12 × 100 ft (1,200 ft²) | ~29.2 t | ~43.8 t |
Maintenance tip
Buy 1–2 extra tons of surface stone and pile it at the end of the drive. Raking in a top-up each spring (and after plowing) is what keeps a gravel driveway flat for decades.
Frequently asked questions
How thick should a gravel driveway be?
6 inches total is the residential standard: 4 in compacted crusher-run base + 2 in surface. On clay, poorly drained ground or with heavy vehicles, go 8–9 in total. Details: thickness guide.
How many tons of gravel for a 100-foot driveway?
A 12 ft × 100 ft lane at the standard 6 in total needs about 29 tons. With 6 in base + 3 in surface, 44 tons.
Can I just use crusher run for the whole driveway?
You can — it compacts hard and is cheapest. Downsides: tracks stone dust into the house and puddles if not crowned. Most people prefer 2 in of #57 on top.
Do I need geotextile fabric under a gravel driveway?
On anything softer than sand, yes — woven geotextile ($0.15–0.40/ft²) keeps base stone from sinking into mud and roughly doubles driveway life.
How much does a gravel driveway cost per square foot?
Materials run $0.60–$1.50/ft² installed by a contractor with grading; DIY materials for a 600 ft² drive land around $500–900 delivered.