A 40 × 10 ft gravel driveway topped with 4 inches of #57 stone takes 133 cubic feet, or 4.94 cubic yards, of stone in place. With a little extra for settling and spillage you order about 5.4 yards, which weighs about 7.6 tons: one dump truck load. The calculator above does the same for any area, depth and stone, in cubic yards, tons, bags and truck loads.
How the calculator works
Enter the length and width and the depth you want, or an area, or the volume or weight if you already know it. Pick the stone. The calculator converts everything to one unit system, so feet, inches and fractions can be mixed, and gives the volume to order, the weight, the number of 0.5 ft³ bags and the truck loads.
Volume
Volume is length × width × depth. With the length and width in feet and the depth in inches, divide the depth by 12 to get cubic feet, then divide by 27 to get cubic yards: 40 × 10 × 4/12 = 133.3 ft³, and 133.3 ÷ 27 = 4.94 yd³.
Compaction and waste
Stone with fines, like crusher run or screenings, compacts when it is rolled or tamped, so you need more loose material than the finished depth suggests: 15 % is a common allowance. Clean stone such as #57 settles only a little, and pea gravel and river rock hardly at all. The waste allowance covers spillage, an uneven subgrade and stone pushed into soft soil. Both are added to the volume, not to a weight you already know.
Weight
Quarries sell by the ton, landscape yards often by the yard, so the calculator gives both. Weight is the loose volume times the density. Densities are not standardized: they are measured by the ASTM C29 method and change with the rock, the gradation and the moisture by 10 % or more. The values below are typical; the density on your supplier's ticket or quote is the one to use, and the calculator accepts it.
| Stone | Typical tons per cubic yard | Typical use |
|---|---|---|
| #57 crushed stone | 1.40 | Drainage, driveway top course, concrete aggregate |
| Crusher run (#411, road base) | 1.45 | Driveway and slab base, compacts hard |
| Pea gravel | 1.35 | Paths, play areas, drainage around pipes |
| River rock | 1.35 | Landscaping beds, dry creek beds |
| Stone screenings | 1.40 | Paver base, joints between flagstones |
| Crushed concrete | 1.25 | Recycled base and fill |
How deep should gravel be?
Depth depends on the job and the soil. A gravel walkway or patio usually takes 2 to 3 in of pea gravel or screenings over landscape fabric. A driveway on firm ground is commonly built as 4 to 6 in of compacted crusher run topped with 2 to 3 in of #57 or similar stone; soft or wet soil needs more base. Under a concrete slab below grade, the IRC calls for a 4 in base of clean graded sand, gravel or crushed stone, except on well-drained soils (R506.2.2). For drainage trenches and French drains, enter the trench length, width and depth; the pipe takes up little enough to ignore.
Bags or bulk
Stores sell gravel and decorative stone in 0.5 ft³ bags, so a cubic yard is 54 bags. That is practical for a planter or a small path, not for a driveway: the 5.4 yards above would be 294 bags. Bulk delivery is cheaper per ton from about one yard up. A tandem dump truck typically carries 14 yd³ or 15 tons, whichever comes first; for stone the weight usually runs out first.
Coverage
At 4 in deep, one ton of #57 stone covers about 52 ft² with the default allowances, about 58 ft² without them. At 2 in deep the coverage doubles. The calculator shows the coverage per ton for the depth you enter.
Common mistakes
- Forgetting to divide the depth by 12. 4 in is 0.33 ft; using 4 overstates the volume twelve times.
- Ordering finished depth of a base stone. Crusher run loses about 15 % of its loose height under a plate compactor.
- Assuming a yard weighs a ton. Stone weighs 1.3 to 1.5 tons per yard; topsoil about 1, mulch less than half.
To convert other materials, use the Cubic Yards to Tons Calculator; for sand, the Sand Calculator; for the concrete slab on top, the Concrete Calculator.