To figure out how much gravel you need, multiply the length by the width in feet, multiply by the depth in inches, and divide by 12 to get cubic feet. Divide by 27 for cubic yards, then multiply by the stone's weight per cubic yard (about 1.4 tons for typical crushed stone, the gravel calculator's default) to get tons. A 30 × 10 ft area 4 inches deep takes 3.70 cubic yards, or about 5.19 tons.
Suppliers sell gravel by the cubic yard or by the ton, so the calculator gives you both. If your supplier quotes a different weight for the stone you pick, enter it.
How to measure for gravel
- Measure the length and width in feet. For a driveway, measure the full width you want covered, not just the tire tracks. For curves or odd shapes, split the area into rectangles and add them.
- Choose the depth. Use the depth table below. For layered jobs like a driveway, calculate each layer separately, since the base and top layers are often different products.
- Measure trenches as boxes. A French drain or a footing trench is length × width × depth. Measure the actual trench width, not the shovel width.
- Decide whether you'll compact it. If you will run a plate compactor or roller over the stone, you need more loose gravel than the finished depth suggests. See the compaction note below.
- Get the weight from your supplier. Stone density varies by rock type and size. The calculator starts at 1.4 tons per cubic yard; change it if your yard quotes something else.
The gravel formula
The calculator uses:
- Cubic yards = length (ft) × width (ft) × depth (in) ÷ 12 ÷ 27
- Tons = cubic yards × tons per cubic yard
Dividing by 12 turns inches into feet, and dividing by 27 turns cubic feet into cubic yards (3 × 3 × 3 ft). Stoneco's gravel guide uses the same volume formula.
Worked example (the calculator's default values)
An area 30 ft long and 10 ft wide, 4 inches deep, with stone at 1.4 tons per cubic yard:
- Volume: 30 × 10 × 4 ÷ 12 = 100 cu ft
- Cubic yards: 100 ÷ 27 = 3.70 cubic yards
- Weight: 3.7037 × 1.4 = 5.19 tons (the calculator uses the unrounded cubic yards, so it does not multiply the rounded 3.70)
The calculator shows: "You need 3.70 cubic yards of gravel. At 1.40 tons per cubic yard, that is about 5.19 tons."
For perspective, Quikrete All-Purpose Gravel comes in 0.5 cu ft bags, so this same job would take 200 bags. Bags suit small patches and post holes; anything this size is a bulk order.
Allow for compaction
Stoneco notes that compaction can reduce gravel volume by as much as 20 percent. To still reach the full depth after a 20 percent loss, divide the calculated volume by 0.8, which is the same as ordering 25 percent more loose stone. For the example above, that is about 4.63 cubic yards, or 6.48 tons. If your supplier gives you a different compaction figure for the stone you pick, use theirs.
Example: a French drain trench
Trenches use the same math with a narrow width and a deep depth. For a trench 50 ft long, 1 ft wide, and 18 inches deep, enter length 50, width 1, and depth 18. That is 50 × 1 × 18 ÷ 12 = 75 cu ft, or 2.78 cubic yards, about 3.89 tons at 1.4 tons per cubic yard. If the trench is 10 inches wide instead of a full foot, enter 0.83 as the width; small changes in width make a big difference over a long run.
Gravel depth by project
| Project | Typical depth |
|---|---|
| Driveway | 4 to 6 in per layer |
| Garden path | About 4 in |
| Patio base | 4 to 6 in |
| French drain trench | Trench 8 to 24 in deep |
Depths are from Stoneco's gravel guide. Its driveway figure is per layer, and driveways are often built in more than one. The Federal Highway Administration's gravel roads guide, for example, calls for at least 6 inches in the first layer when stone goes over stabilization fabric on soft ground. For a paver patio base, use our paver calculator, which sizes the base and sand for you.
Coverage per cubic yard and per ton
| Depth | 1 cubic yard covers | 1 ton covers (at 1.4 tons/yd) |
|---|---|---|
| 2 in | 162 sq ft | About 116 sq ft |
| 3 in | 108 sq ft | About 77 sq ft |
| 4 in | 81 sq ft | About 58 sq ft |
| 6 in | 54 sq ft | About 39 sq ft |
At 1.4 tons per cubic yard, one ton of stone is about 19.3 cubic feet.
How much does gravel weigh?
Weight depends on the rock and how much fine material is mixed in:
| Material | Approximate weight | Source |
|---|---|---|
| Standard crushed stone | 1.35 to 1.4 tons per cubic yard (2,700 to 2,800 lb) | Select Sand & Gravel |
| Crusher run or road base (with stone dust) | Up to about 1.5 tons per cubic yard (3,000 lb) | Select Sand & Gravel |
| Bagged all-purpose gravel | 50 lb per 0.5 cu ft bag, which works out to 1.35 tons per cubic yard | Quikrete bag size |
Denser rock like basalt or trap rock weighs more than limestone, and smaller grades with fines pack tighter. That is why the weight field is editable. For the example, the range from 1.35 to 1.5 tons per cubic yard moves the order from about 5.00 to 5.56 tons.
Picking the right gravel
- For driveways, use crushed stone with fines. The FHWA gravel roads guide explains that good surface gravel needs three parts: stone for strength, sand to fill the gaps, and fine particles to bind it into a firm crust. Stone without enough fines won't form that crust.
- Angular beats round for traffic. According to the same guide, fractured stone embeds into the surface and resists movement much better than rounded, natural stone.
- For drainage and decoration, describe the job to your supplier and ask them to match the stone to it.
Tips for ordering and spreading
- Crown the driveway. The FHWA guide recommends about 1/2 inch of crown per foot of width (roughly 4 percent), and advises not exceeding 6 percent. On a 10 ft wide drive, the center sits about 2.5 inches higher than the edges.
- Compact in layers. The FHWA guide notes that a roller greatly improves the finished surface.
- Order in the supplier's unit. Some quote by the ton and some by the cubic yard; the calculator shows both.
- Have a spot ready. Bulk stone arrives as a pile. Know where the truck can dump it without blocking the work area.
Common mistakes to avoid
- Ordering the finished depth when you plan to compact. Add the compaction allowance. A 20 percent loss needs 25 percent more loose stone, not 20.
- Assuming every stone weighs the same. A heavier stone means more tons for the same cubic yards.
- Mixing inches and feet. The depth field is in inches. Entering 0.33 instead of 4 gives a result twelve times too small.
- Using rounded stone where cars drive. It doesn't lock together the way fractured stone does.
- Ignoring soft ground. On a weak subgrade, the FHWA guide pairs stabilization fabric with a thicker first layer of stone.
Frequently asked questions
How much does a yard of gravel weigh?
Typical crushed stone weighs about 1.35 to 1.4 tons per cubic yard (2,700 to 2,800 lb). Crusher run or road base with stone dust can reach about 1.5 tons. Ask your supplier for the exact figure.
How many tons of gravel do I need for a driveway?
It depends on size and depth. A driveway 60 ft long and 10 ft wide at 4 inches deep needs 7.41 cubic yards, which is about 10.37 tons at 1.4 tons per cubic yard. If you will compact it and expect the full 20 percent loss, order about 25 percent more loose stone: roughly 9.26 cubic yards, or 12.96 tons.
How much area does a ton of gravel cover?
At 1.4 tons per cubic yard, one ton covers about 116 sq ft at 2 inches deep, 77 sq ft at 3 inches, and 58 sq ft at 4 inches.
How many bags of gravel make a cubic yard?
With 0.5 cu ft bags like Quikrete All-Purpose Gravel, it takes 54 bags to make one cubic yard (27 ÷ 0.5).
How deep should gravel be for a path?
Stoneco uses about 4 inches for a garden path. A 40 × 3 ft path at 4 inches needs 40 cu ft, which is 1.48 cubic yards or 80 bags of 0.5 cu ft.
Should I order extra gravel?
Yes, if you'll compact it. Stoneco says compaction can shrink the volume by as much as 20 percent, and it suggests rounding your order up, for example to the next whole cubic yard. For loose decorative gravel you won't compact, the calculated volume rounded up to the supplier's next increment is usually enough.