River Rock Calculator

Calculate river rock for beds, borders and dry creek areas from your measurements, then add your supplier's bulk density if you also need an estimated weight.

River rock volume calculator

Material: River rock · Calculating another material? Use the Gravel Calculator

Units
Area and depth

Section 1

Shape

For a square, enter the same length and width.

Enter the finished depth you plan to use.

Add another area — a second bed or a path, for example — to calculate a combined total.

Advanced optionsExtra material / handling allowance

Adds the percentage you choose to the order volume for waste, handling or contingency. It is separate from compaction.

Result

Your result will appear here

Enter your measurements and calculate to see volume in cubic yards, cubic feet, and cubic metres.

How this calculator works

Enter the shape and size of each area and the finished depth of rock you want. The calculator multiplies area by depth and converts the result to cubic yards, cubic feet and cubic metres.

Volume = Area × Finished depth

Area and depth must use compatible units. The calculator converts them for you.

River rock areas are often irregular. Split them into rectangles, circles and triangles and add each one as a section, or measure the total area and use Known area.

About river rock

River rock is smooth, rounded stone. Suppliers sell it in named size ranges, and a product labelled with a larger size range is a different product from a small one — even when both are called river rock.

Choosing a depth

Larger stones need more depth to cover the ground than smaller stones. This calculator does not recommend a depth; enter the finished depth you plan to use for your chosen size.

Weight depends on the product

The name “river rock” does not tell you the bulk density. Stone size, rock type and moisture all change how much a cubic yard weighs, so ask your supplier for the loose bulk density of the exact product if you need a weight.

Common uses

  • Decorative beds and borders
  • Dry creek beds and drainage swales in the landscape
  • Edging around paths and patios

Important

River rock is not a conventional paver base. CMHA guidance for interlocking concrete pavers warns against smooth river rock as base material. And if you are protecting a slope or channel from erosion, that is riprap design — see the Riprap Quantity Calculator for quantity only.

Combining several beds? The Landscape Rock Calculator is built for multiple areas. For other materials, use the Gravel Calculator.

Worked example

Example: dry creek bed 30 ft long, 4 ft wide, 4 in deep

  1. Area: 30 ft × 4 ft = 120 ft²
  2. Depth: 4 in = 0.3333 ft
  3. Volume: 120 × 0.3333 = 40.0 ft³
  4. Cubic yards: 40.0 ÷ 27 = 1.48 yd³

Result: 1.48 cubic yards (1.13 cubic metres). The depth is an example input, not a recommendation.

Frequently asked questions

How many US short tons of river rock do I need?

Calculate the volume first. Then ask your supplier for the loose bulk density of the river rock you are buying and enter it — the calculator will estimate the weight in US short tons and metric tonnes.

Does stone size change the volume I need?

The volume depends only on your area and finished depth. Stone size affects what depth you choose and how much a cubic yard weighs, not the geometry.

How do I measure a winding creek bed?

Break it into straight runs and treat each as a rectangle, or measure its total area and use Known area. Add each run as a section to get one total.

Can I use river rock under pavers?

Not as a conventional paver base. CMHA guidance for interlocking concrete pavers warns against smooth river rock for the base layer.

Sources & methodology

The volume result is geometry plus unit conversion. Weight uses only the bulk density you enter. Sources relevant to this page: