River rock calculator for Iowa
Stone size changes tonnage coverage: 3-inch rock covers only half the area that 1-inch rock covers per ton.
Enter your project dimensions
Choose stone size before setting depth, since it determines river rock coverage. Ground coverage takes a layer near twice the stone diameter: 1-inch rock needs 2 inches, while 3-inch rock calls for 4 inches or more. As a result, one ton covers half as much space with the larger stone. Select a size and enter the bed measurements in this river rock calculator for a ton estimate based on river rock's 2,700 lb per cubic yard. The delivered amount can also seem smaller than expected. A ton equals only three-quarters of a cubic yard. When fabric shows after the rock is spread, the layer is too shallow, not short on quantity.
Plan the order
- Take bed and border measurements in feet. For separate spaces, multiple-areas mode combines the totals.
- Make the layer twice the rock diameter: 2 inches with 3/4-1 inch stone, 3-4 inches with 1-3 inch stone, and 4-5 inches for larger pieces.
- For cubic yards, divide cubic feet by 27; multiply yards by 1.35 to find tons.
Ton coverage by stone size
| Stone size | Layer depth | 1 ton covers |
|---|---|---|
| 3/4-1" river rock | 2 inches | ≈ 120 sq ft |
| 1-3" river rock | 3 inches | ≈ 80 sq ft |
| Large river rock (2-4") | 4-5 inches | ≈ 53 sq ft |
| Oversize accents | single layer | 35-50 sq ft |
| Project | Typical size | Depth | Volume | Weight |
|---|---|---|---|---|
| Foundation border | 40 x 3 ft | 3" | 1.1 yd³ | 1.5 tons |
| Dry creek bed | 25 x 4 ft | 4" | 1.2 yd³ | 1.7 tons |
| Accent beds | ≈ 150 sq ft | 2" | 0.9 yd³ | 1.3 tons |
| Downspout splash zones, x4 | 3 x 2 ft each | 3" | 0.2 yd³ | 0.3 tons |
| Front-yard xeriscape | ≈ 600 sq ft | 3" | 5.6 yd³ | 7.5 tons |
Install fabric before rock
Bare soil gradually absorbs loose rock, so start with landscape fabric. Stones settle a bit each season, weeds push up, and after three years the bed may need a top-up that a few dollars a roll of fabric could have avoided. Put down non-woven fabric, fasten it with pins, and spread the stone. For drain rock carrying water, wrap the fabric around the stone rather than laying it beneath it.
Natural-looking rock bed ideas
- Use two stone sizes: make the base 1 to 2 inches, then group larger pieces through it. A single size can resemble a parking-lot median.
- Set the largest dry-creek-bed anchor stones one third below grade so they have a water-placed look.
- Once the rock is spread, hose it off. Quarry dust on delivered stone can dull its color until that first rinse.
- To carry roof water away and finish the foundation edge, place a 3 to 4 inch layer over fabric and pitch it gently away from the wall.
- Leaves are easiest to remove with a blower set on low. Raking can send stones into the grass, where they may later meet the mower blades.
Example: a 200-square-foot bed
With one-inch river rock laid 2 inches thick, 200 x 0.167 works out to 33 cubic feet, or 1.2 cubic yards, which is about 1.7 tons. Purchase two tons. Use what remains to double-layer the front edge, since it is the most visible area and usually thins out first.
Rock versus mulch over five years
Because mulch adds to the soil and costs less per delivery, it needs renewing every year or two. River rock has a higher initial cost but generally looks much the same in year five. Summer sun can heat the soil beside it, so mulch often belongs in planted beds, while rock works well at borders, tile outlet drainage, and edges. Enter identical dimensions in both calculators to see how the tonnage changes the price difference.
River rock coverage and pricing questions
How can I figure river rock quantity?
What coverage does 1 ton of river rock provide?
What area will 50 lbs of river rock cover?
What does a ton of river rock cost?
What depth should river rock be?
Is landscape fabric needed under river rock?
Can river rock go on top of mulch?
What is the weight of a yard of river rock?
Other calculators
Planning a rock bed
Buy river rock, large river rock, or drain rock by the ton, with free delivery included.
