Gravel, crushed stone, sand, and road base are all the same estimating problem: a volume of loose material that you order by the cubic yard or, more often, by the ton. The chain is area to volume to weight using the material's density — and the parts that trip people up are choosing tons vs yards, adding for compaction, and picking the right depth. This one guide covers every aggregate the calculators handle.
Every aggregate estimate starts as a volume. Measure the area in feet, decide the depth in inches, convert the depth to feet, multiply, and divide by 27 to get cubic yards (because a cubic yard is 3×3×3 = 27 cubic feet). For irregular areas, split into rectangles and add.
Most suppliers sell aggregate by the ton, so you convert cubic yards to tons using the material's density. Density varies by material and moisture, but these planning figures are close:
| Material | Tons per cubic yard |
|---|---|
| Gravel (dry) | ~1.4 |
| Crushed stone | ~1.4 |
| Sand | ~1.35 |
| Road base / crusher run | ~1.5 |
| Pea gravel | ~1.3 |
Depth is the variable that most changes your order, and it depends on use. Decorative ground cover can be shallow; anything bearing weight needs more, often in layers:
| Application | Depth |
|---|---|
| Decorative ground cover / mulch bed | 2–3 in |
| Walkway / path | 2–4 in |
| Car driveway (total) | 4–6 in |
| Heavy vehicle / poor soil | 8–12 in (layered) |
| Paver / slab sub-base | 4–8 in compacted |
Loose aggregate settles when compacted, so a base course needs more material than the finished depth suggests — add roughly 10–15% for compaction. Deep applications are built in lifts (layers), each compacted before the next, often coarser stone at the bottom and finer on top. A driveway might be 4 in of large crushed stone topped with 2 in of crusher run or pea gravel.
If you order only the loose volume for a base, it will compact below your target depth. Add ~10–15% so the finished, rolled surface hits the depth you planned.
A gravel driveway is the most common aggregate job. Estimate it as a layered base: a coarse bottom layer for drainage and load spreading, then a finer driving surface. Width is usually 10–12 ft for a single lane plus extra for turning. Edging (timber, steel, or a paver border) keeps the gravel from migrating and is measured by the linear foot of perimeter.
Area = 600 sq ft. Volume = 600 × (6÷12) ÷ 27 = 11.1 yd³. Add 12% compaction → 12.4 yd³ × 1.4 = 17.4 tons. Split as ~4 in base stone + 2 in surface gravel.
Crushed stone is graded by size number (the higher the number, the smaller the stone). Common picks: #57 (¾-in, great for drainage and slab base), #411 / crusher run (a mix of stone and fines that compacts hard for driveways), #8 (pea-size, decorative and paver-joint fill), and riprap (large, for erosion control). Pick by function — drainage wants clean uniform stone, a hard driving surface wants graded material with fines.
Aggregate is cheap by the ton but delivery often costs as much as the material, and trucks have minimums. Buying in full truckloads (typically ~10–20 tons) is far cheaper per ton than bagged stone.
| Item | Typical figure |
|---|---|
| Gravel / crushed stone (material) | $15–$45 / ton |
| Pea gravel / decorative | $30–$60 / ton |
| Delivery | $60–$150 / load (distance-based) |
| Truck load | ~10–20 tons |
Use the matching tool for your job — gravel, crushed stone, gravel driveway, or the general material tonnage calculator — then confirm density and load minimums with your supplier.