How the stone calculator works
Stone yards and quarries usually sell decorative and landscape stone by the ton, so this calculator puts tons first. The math is the same as for any loose material:
cubic yards = length (ft) × width (ft) × depth (in) ÷ 12 ÷ 27
tons = cubic yards × lb per cubic yard ÷ 2,000
Worked example
A 15 × 12 ft bed of 3/4 inch white marble chips, 2 inches deep:
- Area: 15 × 12 = 180 sq ft
- Volume: 180 × (2 ÷ 12) = 30 cu ft, or 30 ÷ 27 = 1.11 cu yd
- Tons: 1.11 × 2,700 ÷ 2,000 = 1.5 tons
- With 10% extra: 1.65 tons
Most yards would load that as 1.75 tons. If you buy bagged chips instead, 33 cu ft ÷ 0.5 = 66 bags.
Landscape stone by type
The figures below are typical loose weights. Stone that is wet, or has a lot of fine material mixed in, sits at the heavy end of the range. Ask your supplier for the weight of their product if they have it.
| Stone | Common sizes | About tons per cu yd | 1 ton covers at 2” | 1 ton covers at 3” |
|---|---|---|---|---|
| Crushed granite (decorative) | 3/8”–1” | 1.35 | about 120 sq ft | about 80 sq ft |
| Marble chips | 3/8”–1” | 1.35 | about 120 sq ft | about 80 sq ft |
| Limestone chips | 3/8”–1” | 1.35 | about 120 sq ft | about 80 sq ft |
| River rock | 3/4”–5” | 1.35 | about 120 sq ft | about 80 sq ft |
| Mexican beach pebbles | 1/2”–5” | 1.40 | about 115 sq ft | about 77 sq ft |
| Decomposed granite | fines to 3/8” | 1.30 loose | about 125 sq ft | about 83 sq ft |
| Cobblestone | 3”–8” | 1.30 | n/a (one layer) | n/a (one layer) |
| Lava rock | 3/8”–3” | 0.60 | about 270 sq ft | about 180 sq ft |
The types of landscape rock guide covers what each one looks like and where it works best.
Choosing the depth: twice the stone size
The size you pick in the calculator sets the depth. The rule is about 2 × the average stone size, never less than 2 inches: enough for the stones to overlap and hide the ground. With 3/4 inch stone the rule gives 1.5 inches, so the 2 inch minimum takes over. With 1–3 inch stone the average is about 2 inches, so the depth is about 4 inches. The full table and the reasoning are on the rock calculator.
Loose stone versus solid stone
A cubic yard of loose stone weighs far less than a cubic yard of solid rock, because 35–45% of a pile is air between the stones. Solid granite weighs about 168 lb per cubic foot, which is about 4,500 lb per cubic yard. Pile it up as 3/4 inch chips and the same yard weighs about 2,700 lb.
| Stone | Solid, about lb per cu ft | Solid, about tons per cu yd | Loose (55–65% stone), roughly tons per cu yd |
|---|---|---|---|
| Granite | 168 | 2.27 | 1.25–1.45 |
| Basalt | 180 | 2.43 | 1.35–1.6 |
| Limestone | 160 | 2.16 | 1.2–1.4 |
| Sandstone | 145 | 1.96 | 1.1–1.3 |
| Marble | 170 | 2.29 | 1.25–1.5 |
| Slate | 172 | 2.32 | 1.3–1.5 |
| Quartzite | 165 | 2.23 | 1.25–1.45 |
Use the solid figures for single pieces of stone: the boulder weight calculator, the granite weight calculator, the flagstone calculator and the stone wall calculator all start from them.
Stone coverage in square feet
If you already know how much stone you are getting, flip the formula: square feet = cubic feet ÷ depth in feet. One cubic yard of any stone covers 162 sq ft at 2 inches, 108 at 3 inches and 81 at 4 inches. The rock coverage calculator does this for tons, yards or bags.
Tips for ordering stone
- Round up to the yard’s loading increment. Many yards load in quarter or half tons. Round up rather than down; a few extra shovels of stone are easier to use than a second delivery.
- Ask about delivery minimums. A small order can cost as much to deliver as a large one. See the landscape rock cost guide.
- Check the color wet and dry. Many stones look darker and richer when wet. Look at the pile, not only a photo.
- Keep some back. Decorative stone gets kicked into lawns and settles. A spare bag or two for touch-ups helps match the color later.
These are estimates. Stone from different quarries varies in density and grading, so if your supplier quotes a weight per cubic yard for their stone, use their figure: multiply the calculator's cubic yards by it and divide by 2,000.
Questions people ask
- How do I calculate how much stone I need?
- Multiply length × width in feet, multiply by the depth in inches ÷ 12 to get cubic feet, divide by 27 for cubic yards, then multiply by about 1.35 for tons of most landscape stone. Add 5 to 10 percent for spreading and settling.
- How many square feet does a ton of stone cover?
- A ton of typical decorative stone (about 2,700 lb per cubic yard) is about 20 cubic feet. It covers roughly 120 square feet at 2 inches deep, 80 at 3 inches and 60 at 4 inches.
- How many tons of stone are in a cubic yard?
- About 1.25 to 1.45 tons for most loose landscape stone. Lava rock is the exception at roughly 0.45 to 0.75 tons per cubic yard.
- What depth should decorative stone be?
- About twice the average stone size, with 2 inches as the minimum. For 3/4 inch decorative stone that is 2 inches; for 1 to 3 inch stone it is about 4 inches.
- Is this calculator for stone as a unit of body weight?
- No. This page is about landscape stone. If you meant the weight unit, 1 stone is 14 pounds, or about 6.35 kilograms.