How to use this calculator
- Add each area as a rectangle, a circle or a known number of square feet.
- Choose the type of stone. Each has a typical weight; pick “My supplier’s figure” to enter the exact tons per cubic yard from your supplier.
- Choose the depth and whether to add extra for compaction.
- Optional: enter prices per ton, per yard or per bag to see which is cheapest.
The formulas
- Cubic feet = area (sq ft) × depth (in) ÷ 12, plus any compaction allowance
- Cubic yards = cubic feet ÷ 27
- Tons = cubic yards × tons per cubic yard
- Bags = cubic feet ÷ bag size, rounded up
Worked example
A garden path 30 feet long and 3 feet wide, covered with 3 inches of crushed stone, plus 5% for compaction:
- Area: 30 × 3 = 90 sq ft
- Volume: 90 × 3 ÷ 12 = 22.5 cu ft, plus 5% = 23.6 cubic feet, about 0.88 cubic yards
- Weight at 1.4 tons per yard: 0.88 × 1.4 ≈ 1.2 tons
- In 0.5-cubic-foot bags: 23.6 ÷ 0.5 = 47.3, so 48 bags. At this size, a 1-ton or 1-yard bulk delivery is usually cheaper.
Typical stone weights
| Material | Typical tons per cubic yard |
|---|---|
| Clean crushed stone (#57, #67) | About 1.35 – 1.4 |
| Crusher run / road base (with fines) | About 1.4 – 1.5 |
| Lava rock | About 0.65 – 0.9 |
Crushed stone and road base figures are from aggregate supplier Select Sand & Gravel; lava rock is far lighter because it is porous. For pea gravel and river rock, the calculator starts from the crushed-stone figure. Denser rock such as basalt weighs more than limestone, and wet stone weighs more than dry, so if you are buying by the ton, ask your supplier for their tons-per-yard figure.
Choosing a depth
- Decorative top layer over fabric or an existing base: about 2 inches.
- Walkways and patio surfaces: 2 to 3 inches over firm, well-drained soil or a compacted base.
- Driveways: a deeper, compacted base of larger crushed stone or road base, topped with a few inches of surface stone. Build it in layers and compact each one.
Laying pavers rather than loose gravel? Use our paver base calculator, which adds bedding sand and widens the base past the edges.
Sources
- Select Sand & Gravel: How much does a yard of crushed stone weigh?
- Select Sand & Gravel: How much does a yard of road base weigh?
Frequently asked questions
How much does a cubic yard of gravel weigh?
Clean crushed stone typically weighs about 2,700 to 2,800 pounds per cubic yard, roughly 1.35 to 1.4 tons, according to aggregate supplier Select Sand & Gravel. Crusher run or road base, which contains stone dust, weighs more, up to about 1.5 tons. Weight varies with the type of rock and its moisture.
How do I convert cubic yards of gravel to tons?
Multiply cubic yards by the stone’s weight in tons per cubic yard. For crushed stone at about 1.4 tons per yard, 3 cubic yards is about 4.2 tons. Ask your supplier for their own figure if you are buying by weight.
How many bags of gravel are in a cubic yard?
A cubic yard is 27 cubic feet, so it equals 54 bags of 0.5 cubic feet or 36 bags of 0.75 cubic feet. For more than a yard or so, bulk delivery is usually much cheaper than bags.
How deep should gravel be for a walkway?
Two to three inches of surface gravel is common for a walkway or patio, over a firm, well-drained base. Driveways need much more: several inches of base stone under the surface layer.
Should I order extra gravel?
For compacted stone such as a driveway base, order about 5 to 10% extra to allow for compaction and minor variations. Loose decorative stone needs little or no extra.