Free tool
Gravel & Mulch Calculator
How much rock, decomposed granite, or mulch should you order? Enter your area and depth to get cubic yards, approximate tons, and bag counts.
You need
200 sq ft at 4 in. deep
- Cubic yards
- 2.47
- Tons (approx.)
- 3.51
- 2 cu ft bags
- 34
- 0.5 cu ft bags
- 134
Tons use 1.42 tons per cubic yard for pea gravel (105 lb/ft³ dry). Your supplier's number may differ; ask them for their weight per yard.
Recommended depths
| Use | Depth | Try it |
|---|---|---|
| Decomposed granite path (foot traffic)[4] | 3 in. compacted | 200 sq ft at 3 in. |
| Decomposed granite drive or cart path[4] | 4 in. compacted | 200 sq ft at 4 in. |
| Gravel or rock mulch in planting beds[3] | 2–3 in. | 200 sq ft at 3 in. |
| Wood mulch in planting beds[5] | 3 in. | 200 sq ft at 3 in. |
Material weights we use
| Material | Tons per cubic yard | Notes |
|---|---|---|
| Pea gravel | 1.42[1] | 105 lb/ft³ dry |
| Crushed rock (3/4") | 1.35[2] | about 100 lb/ft³ |
| River rock (1–3") | 1.39[2] | about 103 lb/ft³ |
| Decomposed granite (DG) | 1.25[3] | supplier rule of thumb |
| Lava rock | 0.6–0.74[2] | porous and light; varies |
| Wood mulch | Sold by volume | sold by the cubic yard or bag |
| Compost | Sold by volume | sold by the cubic yard or bag |
Weights are typical dry figures. Wet rock weighs more, and quarries differ, so confirm with your supplier before you size a truck or trailer.
Before you order
Frequently asked questions
How many tons are in a cubic yard of gravel?
It depends on the rock. Typical dry figures: pea gravel about 1.42 tons per cubic yard (105 lb/ft³), crushed rock about 1.35, river rock about 1.39, decomposed granite about 1.25, and lava rock only about 0.6–0.74. Ask your supplier for their weight per yard.
How deep should a decomposed granite path be?
Kafka Granite's pathway specification calls for 3 inches of compacted DG for foot traffic and 4 inches for vehicles, over a compacted base. Order extra, because loose DG settles when you compact it.
How many bags of mulch or gravel make a cubic yard?
A cubic yard is 27 cubic feet, so it takes 13.5 bags of 2 cubic feet, or 54 bags of 0.5 cubic feet. Past a cubic yard or two, bulk delivery is usually cheaper than bags.
How deep should rock or wood mulch be in a xeriscape?
Rock mulch is usually 2–3 inches deep. Wood mulch is commonly 3 inches, the minimum several utility rebate programs require. Keep mulch a few inches back from plant crowns and tree trunks.
Sources
- Engineering ToolBox — Dirt and Mud Densities (gravel, dry: 105 lb/ft³). Source
- GravelCalculator.org — gravel types guide (crushed stone 1,600 kg/m³; river rock 1,650 kg/m³; lava rock ≈1,200 lb/yd³, ≈0.74 t/yd³). Source
- Southwest Boulder & Stone — Coverage Calculator & FAQ (1 yd³ ≈ 1.25 tons for most landscape rock except lava rock and mulch; rock mulch usually 2–3 in. deep). Source
- Kafka Granite — Pathway catalog (standard DG pathway: 3 in. compacted for pedestrians, 4 in. for vehicles). Source
- Albuquerque Bernalillo County Water Utility Authority — Xeriscape rebate (minimum 3 in. of mulch). Source