Quick answer: Multiply length × width × depth to get cubic feet, divide by 27 for cubic yards, then multiply by about 1.4 for tons. A 50 × 12 ft driveway, 6 inches deep, needs about 11.1 cubic yards or 15.8 tons of gravel.
A gravel driveway is one of the most affordable driveway surfaces, but only if you order the right amount of stone. Too little and you get thin spots that rut; too much and you pay for stone you do not need. This guide shows how to calculate the quantity and how deep to make each layer.
The Gravel Formula
Cubic yards = Length (ft) × Width (ft) × Depth (in) ÷ 12 ÷ 27
Tons = Cubic yards × 1.4 (typical gravel)
Most quarries and landscape suppliers sell by the ton, so the weight figure matters. Typical gravel weighs about 2,800 lb per cubic yard, which is 1.4 US tons. In metric, gravel is about 1.6–1.7 tonnes per cubic meter.
How Deep Should a Gravel Driveway Be?
A durable driveway is usually built in three layers, with larger stone at the bottom and smaller stone on top:
- Base layer (4–6 in): large crushed stone about 2–4 in (50–100 mm) that spreads the load and helps drainage.
- Middle layer (3–4 in): medium crushed stone about ¾–1 in (20–25 mm).
- Top layer (2–3 in): smaller angular stone, often with fines that bind together, or decorative gravel.
For a new driveway on soft ground, a total depth of 8–12 inches is common. To refresh an existing driveway, 2–3 inches of top stone is usually enough. Angular crushed stone locks together much better than round pea gravel, which tends to roll under tires.
Skip the math: enter the size and depth of each layer and get cubic yards, tons, m³ and tonnes for different stone types. Open the free Gravel Calculator →
Gravel Needed for Common Driveway Sizes
These figures use 1.42 tons per cubic yard and include no allowance for compaction:
| Driveway size | Depth | Cubic yards | Tons |
|---|---|---|---|
| 30 × 10 ft | 4 in | 3.7 | 5.3 |
| 50 × 10 ft | 4 in | 6.17 | 8.8 |
| 50 × 12 ft | 6 in | 11.11 | 15.8 |
| 60 × 20 ft | 6 in | 22.22 | 31.6 |
| 100 × 12 ft | 8 in | 29.63 | 42.1 |
Allow for Compaction
Gravel settles when it is compacted with a plate compactor or roller, and some of it works into the soil below. Add 10–15% to your total so the finished surface reaches the depth you planned. A geotextile fabric under the base layer helps stop stone sinking into soft soil.
Metric Example
A driveway 15 m long and 3.5 m wide with 15 cm of stone holds 15 × 3.5 × 0.15 = 7.9 m³. At 1.68 tonnes per m³, that is about 13.2 tonnes, or around 14.5 tonnes with 10% extra for compaction.
Tips for Ordering
- Ask your supplier for their exact density; it varies with stone size and moisture.
- Bulk delivery is far cheaper than bags. One ton fills roughly 40 bags of 0.5 cu ft.
- Check delivery truck limits; many trucks carry 10–15 tons per load.
- Edge the driveway with timber, steel or concrete edging to keep the stone in place.
Frequently Asked Questions
How many tons of gravel do I need for a 100 foot driveway?
A 100 × 12 ft driveway at 4 inches deep needs about 14.8 cubic yards, or roughly 21 tons. At 6 inches deep it needs about 31.6 tons.
How much area does a ton of gravel cover?
About 115 sq ft at 2 inches deep, 77 sq ft at 3 inches and 58 sq ft at 4 inches.
What is the best gravel for a driveway?
Angular crushed stone is best because the pieces lock together. Use larger stone for the base and smaller stone with fines on top. Round pea gravel is better suited to paths.
Related Guides
- How Many Bags of Concrete Do I Need? (10×10 Slab and More)
- How Many Concrete Blocks Do I Need for a Wall?
- How Much Mulch Do I Need? Bags, Yards and Coverage
Try the free Gravel Calculator or browse all home improvement calculators.