Decorative rock for a bed
Landscape Rock Calculator
80 sq ft of river rock 2 in deep takes 0.49 cubic yards, about 0.6 tons at 1.216 tons per cu yd, or 23 bags of 0.6 cu ft. Choose the rock, depth and bag below.
Sources checked
Your estimate
0.49 cu yd
13.33 cu ft of river rock over 80 sq ft at 2 in deep.
- Tons to order0.49 cu yd × 1.216 tons per cu yd0.6 tons
- Across the printed weights1.22 to 1.36 tons per cu yd for this rock0.6–0.67 tons
- One ton coversat 2 in deep133 sq ft
- Bags instead13.33 cu ft ÷ 0.6 cu ft per bag, rounded up23 bags
Tons use the weight in the box. Rock sold by the yard and by the ton can differ from these figures; the weighed ticket decides.
How much landscape rock a bed needs
- Measure the bed. The example is 10 ft × 8 ft, which is 80 sq ft. A round or irregular bed is split into rectangles.
- Multiply the area by the depth in inches and divide by 12: 80 × 2 ÷ 12 = 13.33 cu ft.
- Divide by 27 for cubic yards: 13.33 ÷ 27 = 0.49 cu yd. Rock is sold by the yard or by the ton, so this is the number to compare with the yard’s price list.
- Multiply by the weight of a cubic yard to get tons: 0.49 × 1.216 = 0.6 tons for river rock.
- Divide the cubic feet by the bag’s volume and round up: 13.33 ÷ 0.6 = 22.2, so 23 bags.
Cubic yards come from the area and the depth; tons come from the weight of a yard of the rock, which the producers’ calculators in our data print. The university guides give one inch for a layer of rock used as mulch, and the form starts at 2 in, a depth you choose. University of Maryland Extension, Mulching Trees and Shrubs (2023); Mississippi State University Extension, P2301, Table 1
- Weight of river rock, loose
- 1.216 tons per cu ydGraniterock, Southside 1 1/2 in round rock product page
- Weight of 3/4 in crushed rock
- 1.32 tons per cu ydMartin Marietta aggregates calculator
- Rock as a mulch layer
- 1 in, per the Maryland guideUniversity of Maryland Extension, Mulching Trees and Shrubs (2023); Mississippi State University Extension, P2301, Table 1
- One bag, the reference size
- 0.6 cu ftSakrete All Purpose Gravel data sheet
Square feet one ton covers, by depth and rock
| Depth | Cu yd per 100 sq ft | river rock | 3/4 in crushed rock | lava rock |
|---|---|---|---|---|
| 1 in | 0.31 | 266 sq ft | 245 sq ft | Type your weight |
| 2 in | 0.62 | 133 sq ft | 123 sq ft | Type your weight |
| 3 in | 0.93 | 89 sq ft | 82 sq ft | Type your weight |
| 4 in | 1.23 | 67 sq ft | 61 sq ft | Type your weight |
A ton covers half as much area at 4 in as at 2 in. Read a depth off this table, or enter your bed in the form above for the whole order.
Rock types and their printed weights
| Rock | Tons per cu yd | Printed by |
|---|---|---|
| River rock (round, 1 1/2 in) | 1.216 | Graniterock 1 1/2 in round rock, loose Graniterock, Southside 1 1/2 in round rock product page |
| 1.355 | Graniterock 1 1/2 in round rock, rodded Graniterock, Southside 1 1/2 in round rock product page | |
| 3/4 in crushed rock | 1.32 | Martin Marietta coarse, limestone Martin Marietta aggregates calculator |
| 1.32 | Martin Marietta coarse, granite Martin Marietta aggregates calculator | |
| 1.4 | Martin Marietta coarse, traprock Martin Marietta aggregates calculator | |
| 1.296 | Vulcan coarse aggregates, limestone Vulcan Materials aggregate tonnage estimator | |
| Lava rock | Not published | No document in our data weighs lava rock. Type the weight per cubic yard from your supplier or the bag label. |
Across the printed weights a cubic yard of 3/4 in crushed rock runs from 1.3 to 1.4 tons, and round river rock is lighter loose than rodded. A yard sells by the loose yard or the ton, so the loose figure is the one the form starts from.
Bags or bulk delivery for a bed
A bag holds 0.6 cu ft in our reference, so a cubic yard takes 45 bags. Bags suit a small bed; a bed of a cubic yard or more is usually quicker and cheaper delivered loose. Sakrete All Purpose Gravel data sheet
Where sources disagree
Weight of a cubic yard of river rock
- 1.216 tons per cu yd, Graniterock 1 1/2 in round rock, looseGraniterock, Southside 1 1/2 in round rock product page
- 1.355 tons per cu yd, Graniterock 1 1/2 in round rock, roddedGraniterock, Southside 1 1/2 in round rock product page
The form uses the loose figure, 1.216 tons, because rock is ordered as loose yards. The rodded figure is the same stone packed down and is 0.14 tons heavier per yard. Type the ticket weight if it differs.
Weight of a cubic yard of 3/4 in crushed rock
- 1.32 tons per cu yd, Martin Marietta coarse, limestoneMartin Marietta aggregates calculator
- 1.32 tons per cu yd, Martin Marietta coarse, graniteMartin Marietta aggregates calculator
- 1.4 tons per cu yd, Martin Marietta coarse, traprockMartin Marietta aggregates calculator
- 1.296 tons per cu yd, Vulcan coarse aggregates, limestoneVulcan Materials aggregate tonnage estimator
The form uses Martin Marietta’s coarse limestone, 1.32 tons. Vulcan prints a little less and traprock more; the four are within about a tenth of a ton of each other.
How deep a layer of decorative rock should be
- 1 in, gravel, stone or lava rock as a mulch layer (UMD)University of Maryland Extension, Mulching Trees and Shrubs (2023)
- 1 in, gravel or pebbles as a mulch layer (MSU)Mississippi State University Extension, P2301, Table 1
Both extension guides say one inch for a mulch layer of rock. Our data has no depth by rock size, so the form starts at 2 in, a depth you choose.
Before you order rock
Rock here is a mulch layer on top of a bed. Stone under a patio or a slab is a base: the gravel calculator sizes that in tons. For a bed of bark or chips instead of stone, the mulch calculator gives the volume.
Decorative rock is ordered by the yard, so check the yard’s price list before you buy: it may sell rock by the ton, and a ticket weighed on the scale decides the bill.
Landscape rock questions
How much landscape rock do I need for 80 square feet?
80 sq ft at 2 in deep is 0.49 cubic yards. In river rock that is about 0.6 tons, or 23 bags of 0.6 cu ft.
How many tons of rock is a cubic yard?
About 1.22 tons for loose river rock and 1.32 tons for 3/4 in crushed rock. Lava rock has no weight in our data, so the form asks you to type it.
How many cubic yards of rock for 100 square feet?
At 1 in deep it is 0.31 cu yd; at 2 in it is 0.62 cu yd, and every added inch adds the same again. Read the depth you want off the table above and scale it to your area.
How many square feet does a ton of rock cover?
At 2 in deep, a ton of river rock covers about 133 sq ft, and a ton of 3/4 in crushed rock about 123 sq ft. Denser stone covers less.
How deep should decorative rock be?
Both University of Maryland and Mississippi State name one inch for gravel, stone and lava rock used as a mulch layer. Neither gives a depth for each rock size, so the form starts at 2 in as an example, not a recommendation, and takes any depth you type.
How many bags of landscape rock make a cubic yard?
A cubic yard is 27 cu ft, so 45 bags of 0.6 cu ft. The bag size is a box in the form; use the volume printed on your bag, since rock bags vary.
A planning aid, not an engineering calculation: your local code and building inspector have the final word. Terms