How much gravel do I need?
Cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27
Tons = cubic yards × tons per cubic yard
A 20 × 12 ft area 4 inches deep is 80 cubic feet, or 2.96 cubic yards. Crushed stone weighs about 1.4 tons per yard, so that is about 4.1 tons, or 4.6 tons with 10% extra.
Worked example: a 20 × 12 ft parking pad
- Area. 20 ft × 12 ft = 240 sq ft.
- Depth in feet. 4 inches ÷ 12 = 0.333 ft.
- Volume. 240 × 0.333 = 80 cubic feet. Divide by 27 to get 2.96 cubic yards.
- Add extra. 10% for settling and spills brings it to 3.26 cubic yards.
- Convert to tons. 3.26 × 1.4 tons per yard for 3/4" crushed stone = 4.56 tons. Order 4.5 to 5 tons.
- Price it. At $40 per ton that is about $183 before delivery.
Curved and odd-shaped areas
Split the area into simple shapes, work out each one in square feet, add them up and type the total into the Or total area box above.
- Rectangle: length × width.
- Circle: 3.14 × radius × radius. A round fire pit area 12 ft across has a 6 ft radius: 3.14 × 6 × 6 = 113 sq ft.
- Triangle: base × height ÷ 2.
- L-shaped path: treat it as two rectangles that do not overlap.
Depth by project
| Project | Depth | Notes |
|---|---|---|
| New driveway | 8 to 12 in total | 4 to 6 in of crusher run base, 2 to 4 in of 3/4" stone on top |
| Driveway top-up | 2 to 3 in | Over an existing compacted base |
| Walkway | 2 to 3 in | Pea gravel or 3/8" stone over fabric |
| French drain | Fill the trench | Washed #57 stone around perforated pipe |
| Decorative bed | 2 to 3 in | Over landscape fabric |
Why loads come up short
Stone with fines, like crusher run, packs down when it is driven on or rolled, so a compacted base needs more material than its finished depth suggests. Soft ground also swallows the first inch or two of stone. That is what the extra percentage is for: use 10% for a normal job and 15% for soft ground or an irregular area.
Need volume only? Use the cubic yard calculator. Laying pavers? Base gravel goes under 1 inch of sand from the sand calculator. Comparing materials by weight? See the material weight chart.
Typical depths and coverage for gravel
How deep to lay gravel depends on the job, so treat these depths as common starting points and defer to your plans or the product label. Coverage is how much ground one cubic yard of gravel, or one ton, spreads at that depth.
| Project | Depth | 1 cubic yard covers | 1 ton covers |
|---|---|---|---|
| Garden path or walkway | 3 in | 108 sq ft | 77 sq ft |
| Patio or shed base | 4 in | 81 sq ft | 58 sq ft |
| Driveway top layer over a base | 4 in | 81 sq ft | 58 sq ft |
| Driveway built from scratch | 6 in | 54 sq ft | 39 sq ft |
| Drainage trench or French drain | 12 in | 27 sq ft | 19 sq ft |
Three worked gravel jobs
Each job below adds 10% to the gravel volume for settling and spills, and converts to tons at 1.4 tons per cubic yard.
| Job | Size | Cubic yards | With 10% extra | Tons to order |
|---|---|---|---|---|
| Garden path | 30 × 3 ft at 3 in | 0.83 | 0.92 | 1.3 |
| Shed base | 12 × 10 ft at 4 in | 1.48 | 1.63 | 2.3 |
| Driveway | 40 × 12 ft at 4 in | 5.93 | 6.52 | 9.1 |
Before you order gravel
- Ask the yard what the stone is called and what it weighs per cubic yard. Crushed stone, #57 stone, pea gravel and crusher run all differ.
- Angular crushed stone locks together and suits driveways. Rounded pea gravel stays loose and suits paths and play areas.
- A fabric layer under the stone keeps it from sinking into soft soil, so you lose less to the ground.
- Compare the delivered price per ton, because a short load or a long haul can cost more than the stone.
How many yards of gravel are in a ton?
About 0.7 cubic yards of crushed stone make one ton, because a yard weighs roughly 1.4 tons. Pea gravel is a little lighter, so a ton is about 0.77 cubic yards. Ask your quarry for its weight per yard, since moisture and fines change it.
How deep should gravel be for a driveway?
Plan 8 to 12 inches in total for a new driveway: 4 to 6 inches of compacted crusher run as the base, then 2 to 4 inches of 3/4-inch crushed stone on top. Over a sound existing base, a 2 to 3 inch top-up is enough.
Frequently asked questions
How much gravel do I need for a driveway?
A 12 × 50 ft driveway with 4 inches of base and 2 inches of top stone needs about 11 cubic yards, roughly 16 tons.
How much does a yard of gravel weigh?
About 1.4 tons for crushed stone and 1.3 for pea gravel. It varies with stone size, moisture and fines.
How much area does a ton of gravel cover?
About 80 sq ft at 3 inches deep, or 60 sq ft at 4 inches, for crushed stone.
How many bags of gravel equal a yard?
54 bags of 0.5 cubic feet.
How do I calculate tons of gravel for a driveway?
Multiply length, width and depth in feet to get cubic feet, divide by 27 for cubic yards, then multiply by the stone's tons per yard. A 40 by 12 ft driveway 4 inches deep is 5.93 cubic yards, or about 8.3 tons of crushed stone at 1.4 tons per yard.
How much does a driveway gravel job cost?
Enter the price per ton from your supplier in the calculator. Material cost is tons times price, and delivery is usually extra, so ask for the delivered price per ton.
Sources
Reference charts
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