Gravel Driveway Calculator
Measure your driveway, choose your stone, and see exactly how much to order - in tons, cubic yards, bags, and dollars. Add odd-shaped areas, stack a hard base under a finish layer, and add a little extra for compaction and spillage. Everything runs in your browser, nothing uploaded.
Per-layer breakdown
Learn more: sizing gravel for a driveway
From area and depth to tons
The math is always the same: area times depth gives volume, and volume times the stone's bulk density gives weight. Say your driveway is 30 ft long and 10 ft wide - that is 300 square feet. Spread pea gravel 3 inches deep and you have 300 × (3 ÷ 12) = 75 cubic feet, which is 75 ÷ 27 = 2.78 cubic yards. Pea gravel weighs about 1.4 US tons per cubic yard, so that is roughly 4 tons. Switch to metric and the same driveway is about 27.9 m², 0.075 m deep, 2.1 m³, and 3.6 tonnes.
Why a base layer changes the number
Most driveways are not one layer of stone. A typical build puts a 4 inch compacting base (crusher run or road base, which is heavy at roughly 2.0 tonnes per cubic metre because of its mix of stone and fines) under a 2 inch decorative top such as pea gravel or river rock. Because the two layers have different depths and different densities, you have to weigh them separately and add the totals - which is exactly what the per-layer breakdown does. Crusher run also compacts hard, so it needs a compaction allowance that the loose top stone does not.
Compaction, overage, and how much to actually order
Loose aggregate settles when it is rolled, so a base layer ordered at its finished depth will come up short. Adding a 15-20% compaction allowance for crusher run covers that loss; clean decorative stone barely moves, so 0-5% is plenty. On top of that, a small overage buffer (5-10%) covers spillage, uneven ground, and the bit that disappears into soft spots. Suppliers sell bulk gravel by weight, so the cost estimate multiplies your total tons or tonnes by the price you enter; in bag mode it counts whole bags instead and multiplies by the price per bag.
FAQ
How many tons of gravel do I need for my driveway?
Multiply the area by the depth to get volume, then multiply by the material's bulk density. For example, 300 square feet at 3 inches of pea gravel is about 2.78 cubic yards, roughly 4 US tons, since pea gravel weighs about 1.4 tons per cubic yard. This calculator does that for every layer and adds them together.
What is a compaction allowance and how much should I add?
A compaction allowance is the extra loose gravel you order so a layer still reaches its target depth after it settles and is rolled. Crushed base such as crusher run can lose 10 to 20 percent of its loose volume when compacted, so 15 to 20 percent is common for base layers. Clean decorative stone barely compacts, so 0 to 5 percent is usually enough.
How many bags of gravel equal a bulk ton?
It depends on bag size and stone density, not a fixed number. One US ton of typical gravel is roughly three-quarters of a cubic yard, and a standard half-cubic-foot bag holds about 0.0185 cubic yards, so a ton works out to around 40 bags of that size. Switch to bag delivery and set your real bag size for an exact count.