MaterialSum

Landscape Rock Calculator

Pick your rock type, measure the bed, and get the exact volume, tonnage, and bag count to order.

Dimensions
ft
ft
in
Material & Waste
Optional Cost
Enter your measurements above to see results.

How to use the Landscape Rock Calculator

  1. Measure the bed area (length × width or total area).
  2. Enter depth — 2 in for decorative rock over weed fabric, 3–4 in if it must suppress weeds on its own.
  3. Choose your rock type; each has its own typical density.

Formula & methodology

Volume = Area × Depth. Densities (loose): river rock ~100 lb/ft³, lava rock ~55 lb/ft³, crushed granite ~96 lb/ft³, limestone ~105 lb/ft³, marble chips ~100 lb/ft³.

Example

A 10 ft × 8 ft bed at 2 in of river rock: 80 ft² × 0.167 ft ≈ 13.3 ft³ ≈ 0.5 cu yd, about 0.6 tons or 27 bags of 0.5 cu ft.

Related calculators

Gravel CalculatorMeasure your area, choose a depth, and instantly see how much gravel to order in cubic yards, tons, or bags.Mulch CalculatorFind out how much mulch your garden beds need — whether you buy by the bag or by the truckload.Pea Gravel CalculatorPea gravel is sold by volume and weight — get both numbers, plus bag counts, before you order.Topsoil CalculatorMeasure the area and the depth of new soil you want — get cubic yards, bag counts, and approximate weight for delivery.

FAQ

How deep should landscape rock be?

2–3 inches over landscape fabric is standard. Lava rock is sometimes laid 3 in deep because it is so light (about half the weight of river rock per volume).

How much does a yard of river rock weigh?

Around 2,500–2,700 lb (1.25–1.35 tons). A half-ton pickup safely carries about one yard.

How do I stop weeds under landscape rock?

Use quality landscape fabric (not plastic) under the rock, and overlap seams 6–8 in. Rock alone rarely stops weeds.

Which rock is cheapest for large areas?

Crushed stone and pea gravel in bulk are usually cheapest; specialty rock like marble chips costs several times more per yard.