Landscape Rock Calculator

By the YardCalc team. Updated November 10, 2026.

Enter the bed size and depth and pick the rock. You get tons, cubic yards, bags, how far one ton spreads at that depth, and cost.

For curved or odd shapes, add up the parts and enter the total. It replaces length and width.
1.31
Tons
0.97
Cubic yards
80 sq ft
One ton covers
$105
Est. cost

How much river rock do I need?

Tons = length × width × depth (ft) ÷ 27 × tons per cubic yard

LengthWidthDepth
Measure length and width in feet and depth in inches. The calculator converts everything to cubic yards.

A 10 × 10 ft bed at 3 inches is 25 cubic feet, about 0.93 cubic yards. River rock weighs about 1.35 tons per yard, so that is 1.25 tons. Lava rock is far lighter, about 0.5 tons per yard, so the same bed takes under half a ton.

How deep should landscape rock be?

Rock sizeDepth
Pea gravel, decomposed granite (under 1/2 in)2 to 3 in
3/4 to 1-1/2 in river rock2 to 3 in
1 to 3 in river rock3 to 4 in
3 to 5 in cobble4 to 6 in

A good rule is a depth of about twice the size of the largest stones, so no fabric shows through.

Rock does not break down like mulch. Lay landscape fabric first and edge the bed. Rock lasts for decades, but weeds and soil washing in will bury it without a barrier. For driveways and drainage stone, use the gravel calculator.

Frequently asked questions

How much does a ton of river rock cover?

About 80 sq ft at 3 inches deep, or about 120 sq ft at 2 inches.

How much does a yard of river rock weigh?

About 1.3 to 1.4 tons, depending on stone size and moisture.

Is lava rock lighter than river rock?

Yes, much lighter. Lava rock is about 0.5 tons per cubic yard, so one ton covers roughly 2.5 times the area of river rock at the same depth.

Reference charts

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Last updated November 10, 2026. Results are estimates for planning. See how we build and check our tools in our editorial policy. Found an error? Tell us.