Rock calculator: tons of landscape rock to order
River rock 3/4 to 1 1/2 inch across is laid by the inch and bought by the ton. A 15 by 8 ft bed covered 3 inches deep takes 30 cubic feet, 1.1 cubic yards, or 1.2 yards with 10% extra. At the Ohio DOT's 2,500 pounds per loose yard of rounded gravel, that is 1.5 tons. Larger rock and lava rock take your supplier's own weight.
Area, depth and the weight of the stone
Landscape rock is laid by the inch and bought by the ton, so the calculator converts twice. Each bed's area times the depth gives cubic feet in place. The extra allowance covers low spots and the stones that roll into the lawn. Dividing by 27 gives cubic yards, and multiplying by the stone's weight per cubic foot gives pounds and tons. The weight is the figure that varies most. Rounded gravel, crushed stone and crusher fines have published loose weights from the Ohio DOT. Anything else, from 4 inch cobbles to lava rock, needs the number from the supplier's own ticket, which the density box takes.
Cubic yards = area (sq ft) × depth (in) ÷ 12 ÷ 27, then × (1 + extra). Tons = cubic yards × pounds per yard ÷ 2,000. One ton covers = 2,000 ÷ pounds per cubic foot ÷ depth (ft) square feet.
Weight and coverage of the rock with published figures
| Rock | Loose weight per cubic yard | Tons per yard | One ton covers at 2 in | at 3 in | at 4 in |
|---|---|---|---|---|---|
| River rock or rounded gravel, 3/4 to 1 1/2 in (No. 57, No. 4) | 2,500 lb | 1.25 | 130 sq ft | 86 sq ft | 65 sq ft |
| Crushed limestone, 3/4 in (No. 57) | 2,400 lb | 1.20 | 135 sq ft | 90 sq ft | 68 sq ft |
| Crusher fines, crusher run or decomposed granite | 2,700 lb | 1.35 | 120 sq ft | 80 sq ft | 60 sq ft |
Weights are the Ohio DOT's for stone measured loose in the delivery vehicle. Decomposed granite is crushed granite with fines, so the crusher run figure is the nearest published one. A supplier's own weight is better. Wet rock weighs more. What a cubic yard weighs lists the published stone weights.
A rock bed along a 40 ft fence
The bed is 40 ft long and 5 ft wide, 200 square feet, with three shrubs whose root zones get mulch instead. Take out about 15 square feet for them as a second area subtracted, leaving 185. The rock is 1 inch river rock at 3 inches deep: 185 × 0.25 = 46 cubic feet, or 1.7 cubic yards. With 10% extra that is 1.9 yards. At 2,500 pounds per yard that is 2.4 tons, or 102 bags of 0.5 cubic feet, which is a clear case for a bulk delivery. Fabric for the bed is 200 square feet plus 10% for overlaps. Edging to keep the rock in is the perimeter, 90 linear feet.
Choosing a depth
The depth presets are matched to the stone: 2 inches for 3/4 inch rock and 3 inches for 1 to 2 inch rock. For 2 to 3 inch stone it is 4 inches, and for cobbles 6 inches. The presets are the calculator's own rule of about two stones thick, not a published standard; Utah State's figure for stone mulch is 2 to 3 inches. So the fabric never shows, and the top stones do not roll off the ones below. Measure the depth you want with the actual stone in hand before ordering. Sizes differ, because 1 inch rock from one yard is 2 inch rock from another.
Buying rock in bulk
Landscape yards sell by the ton, the half ton and the scoop. The scoop size differs from yard to yard, so ask what it holds. Delivery is usually charged per load, so measure every bed before the truck comes and order once. Give the yard the tons from the list and the size of stone. Ask whether the price is per ton or per yard before comparing it with the bag price, which the options box prices for you.
Questions about buying landscape rock
How many tons of rock do I need?
Area in square feet times depth in feet gives cubic feet. Divide by 27 for yards and multiply by the stone's weight per yard for tons. A 200 square foot bed at 3 inches is 50 cubic feet, or 1.85 yards. At 2,500 pounds per loose yard for rounded river gravel that is 2.3 tons. Add 10% for low spots.
How much does a ton of rock cover?
At 2,500 pounds per yard, one ton is 21.6 cubic feet. That covers about 130 square feet at 2 inches deep, 86 at 3 inches and 65 at 4 inches. Lighter rock such as lava covers more per ton and heavier crusher fines less. That is why the list recomputes the coverage from the weight you choose.
How deep should landscape rock be?
Deep enough that the fabric or soil underneath never shows, which the calculator's presets take as about two stones' thickness. The depth presets run from 2 inches for 3/4 inch rock up to 6 inches for stone several inches across. Utah State's extension puts stone mulch at 2 to 3 inches, and the presets go deeper for larger stone so the layer stays about two stones thick.
How much does a yard of river rock weigh?
The Ohio DOT measures loose rounded gravel in the 3/4 to 1 1/2 inch sizes (No. 57 and No. 4) at 2,500 pounds per cubic yard. It measures crushed stone with fines at 2,700. Larger cobbles and lava rock have no figure from a public source. Suppliers quote their own, and the density box takes it.
Should I put landscape fabric under rock?
Fabric is a choice, not a rule. It keeps the stone and the soil from mixing and makes the stone easier to move later, and weeds still seed into the dust that collects on top. If you use it, lay the stone to the full depth so the fabric never shows.
Is river rock sold by the ton or the yard?
Bulk river rock and crushed stone are usually sold by the ton because the yard weighs the truck. Light rock is often sold by the cubic yard. Bags at the garden center are 0.5 cubic feet, and there are 54 of them in a cubic yard. The list shows all three so you can compare whichever unit the quote is in.
How much rock do I need for a dry creek bed?
Treat the creek as a long rectangle using its average width, then add the larger stones along the edges separately. A 30 ft creek averaging 3 ft wide, filled 4 inches deep with river rock, is 30 cubic feet, 1.1 yards, about 1.4 tons. Add the bank stones, which are priced by the ton or by the piece.
2 source documents
- Ohio Department of Transportation, Construction and Material Specifications, Item 410 Traffic Compacted Surface, Table 410.06-1 (loose weights of gravel, limestone and crusher run), 2013 specifications. Read 2 November 2026.
- Utah State University Extension, Water-Wise Landscaping: Mulch (inorganic mulch 2 to 3 inches deep, organic 3 to 4). Read 2 November 2026.