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.
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.
Sources
Reference charts
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