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River Rock Calculator

Construction

Calculate how many tons and cubic yards of decorative river rock you need. Enter your area's length, width, and depth for an accurate landscaping estimate.

1500
1500
0.524
1.11.6

River Rock Needed (tons)

2.41
Volume (cubic yards)
1.85

This calculator computes your River Rock Needed (tons), Volume (cubic yards) from the values you enter.

Inputs
LengthWidthDepthDensity
Outputs
River Rock Needed (tons)Volume (cubic yards)

What is a River Rock?

A River Rock Calculator estimates the tons and cubic yards of decorative river rock needed to cover a garden bed, dry creek bed, or drainage area to a chosen depth. River rock is naturally tumbled, rounded stone — typically 1 to 8 inches across — prized in landscaping for its smooth appearance, natural color variation, and use in low-maintenance ground cover that doesn't require mowing or regular replacement.

Because river rock is sold by the ton and pricing varies with color and size, an accurate estimate before ordering avoids both overspending on excess material and the hassle of a mismatched second delivery. This calculator converts your bed's length, width, and target depth into cubic yards, then applies a density figure to produce a tonnage you can quote directly with a landscape supplier. For structural erosion-control stone rather than decorative rock, see the Rip Rap Calculator instead.

How to use this River Rock calculator

  1. Enter the Length of the area to be covered, in feet.
  2. Enter the Width of the area, in feet.
  3. Enter the Depth of the river rock layer, in inches — 3 in is a common default for decorative ground cover.
  4. Adjust the Density slider to match your supplier's tons-per-cubic-yard figure for your chosen rock size, typically 1.1-1.6.
  5. Read the River Rock Needed (tons) result to place your order, and check Volume (cubic yards) if your supplier prices by the yard.

Formula & Methodology

The calculation converts area and depth into cubic yards, then applies stone density:

Cubic feet = Length x Width x (Depth ÷ 12)

Cubic yards = Cubic feet ÷ 27

Tons needed = Cubic yards x Density (tons/yd³)

Worked example: A 20 ft by 10 ft garden bed with a 3 in river rock depth and a density of 1.3 tons/yd³:
- Cubic feet = 20 x 10 x (3 ÷ 12) = 50 ft³
- Cubic yards = 50 ÷ 27 = 1.85 yd³
- Tons needed = 1.85 x 1.3 = 2.41 tons

At a typical delivered price of $70/ton, this project would run roughly $169 in stone before landscape fabric or delivery fees.

Frequently Asked Questions

For a 20 ft by 10 ft bed at a 3 in depth, you'd need roughly 2.4 tons of river rock. Enter your exact length, width, and depth into the River Rock Calculator to get a tonnage figure matched to your specific area.
Multiply length x width x depth (with depth converted from inches to feet) to get cubic feet, then divide by 27 to get cubic yards. Multiply the cubic yards by the stone's density in tons per cubic yard to get total tons needed.
River rock is naturally rounded, smooth stone typically 1-4 in in size, prized for decorative landscaping, dry creek beds, and drainage areas. Gravel is crushed, angular aggregate used more for structural base layers and driveways — see the [Gravel Calculator](/gravel-calculator/) for those projects.
A 2-3 in depth is standard for decorative ground cover and garden beds, while dry creek beds or drainage channels often use 4-6 in for better water flow. Deeper applications need proportionally more material, so adjust the Depth input accordingly.
River rock typically weighs 1.2 to 1.4 tons per cubic yard, lighter than angular gravel because of its rounded shape and resulting void space. Check with your supplier for the exact density of the specific rock size and type you're purchasing.
Landscape fabric or weed barrier is strongly recommended under river rock to prevent weed growth and stop the stone from sinking into the soil over time. This doesn't change the tonnage calculation but should be included in your overall project budget.
River rock in the US typically costs $40-$120 per ton depending on size, color, and region, with polished or specialty colored rock at the higher end. Bulk delivery usually brings the per-ton price down compared to bagged river rock from a home center.
Yes, river rock's rounded shape creates good void space for water to pass through, making it a popular choice for French drains, dry creek beds, and drainage swales. For erosion control on slopes or stream banks, larger [rip rap](/rip-rap-calculator/) stone is typically more effective than decorative river rock.
A mix of 3-5 in and 5-8 in river rock creates the most natural-looking dry creek bed, often combined with a few larger accent stones. Smaller 1-2 in pea gravel-sized river rock works better for pathways and ground cover than for simulating a creek bed.
A standard 0.5 cubic foot bag of river rock weighs roughly 40-50 lb, so a ton (2,000 lb) requires about 40-50 bags. Buying in bulk by the ton or cubic yard is significantly more economical than bagged rock for any area larger than a small garden bed.
River rock provides a permanent, low-maintenance decorative surface that doesn't wash away, while [sand](/sand-calculator/) is typically used as a leveling base layer under pavers or in play areas rather than as a finished surface. The two materials serve different structural roles in most landscaping projects.
Also known as
river rock coverage calculatordecorative rock calculatorhow much river rock do I needlandscaping rock calculatorriver rock tonnage calculator