Stone Calculator

A stone calculator returns the cubic yards and tons of landscape stone a bed or border needs. It multiplies the area by the depth, adds a waste allowance, converts the volume to cubic yards, then multiplies by the stone's density in tons per cubic yard.

Last reviewed September 2026Method & sources Report an error

Not to scale.

Stone Needed (with waste)

0.81 cu yd

Includes a 10% waste allowance.

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Landscape stone1.22 tonsAbout 0.81 cu yd.
Bagged

Breakdown
Stone Needed (with waste)	0.81 cu yd
Stone Needed	1.22 tons
Estimated Cost

How to Calculate Stone

Volume is Area × Depth, with depth converted from inches to feet, plus a waste allowance for settling and overspill at edges. The result converts to cubic yards, then to tons using a density figure. Decorative and landscape stone density varies more than most bulk materials. It runs roughly 1.2 to 2.2 tons per cubic yard depending on the specific stone type and size (lighter, more angular pieces settle with more air gaps than dense, rounded river rock, for example). Density here is an adjustable input, defaulting to 1.5 tons per cubic yard, a reasonable general planning figure.

Example: 20 ft × 4 ft border, 3 in. depth, default 1.5 tons/cu yd density

A 20 ft × 4 ft border, 3 in. depth, default 1.5 tons/cu yd density, 10% waste: 1. Area: 20 × 4 = 80 sq ft 2. Depth in feet: 3 ÷ 12 = 0.25 ft 3. Raw volume: 80 × 0.25 = 20 cubic feet 4. With 10% waste: 20 × 1.10 = 22 cubic feet 5. Cubic yards: 22 ÷ 27 ≈ 0.81 cubic yards 6. Tons: 0.81 × 1.5 ≈ 1.22 tons. A lighter lava rock (closer to 1.2 tons/cu yd) on the same border would need only about 0.98 tons. Checking your specific stone product's density matters more here than for most bulk materials.

Stone: Compare Scenarios

Scenario	Stone Needed (with waste)	Stone Needed
Small (10×2 ft border)	0.14 cu yd	0.20 tons
Medium (20×4 ft border)	0.81 cu yd	1.22 tons
Large (50×8 ft bed)	4.07 cu yd	6.11 tons

What Is Stone?

A stone calculator converts an area and desired depth into the tons of decorative or landscape stone needed. Tons rather than a bag or piece count, since stone is bought and delivered by weight. Density is kept adjustable because "stone" covers a wide range of products (crushed granite, river rock, lava rock, marble chips, and more), each packing to a meaningfully different weight per cubic yard.

Stone: Pros and Cons

Pros

Adjustable density accounts for the wide range of products sold as "stone". From lightweight lava rock to dense river rock
Includes a settling/overspill allowance on top of the raw volume calculation
Gives the answer in tons, matching how landscape stone is actually priced and delivered

Cons

Doesn't recommend a stone type or size for your project. That's a design decision based on look, drainage needs, and walkability
Assumes a simple rectangular area. An irregular bed or border needs its area estimated separately or broken into sections
The default 1.5 tons/cu yd density is a general planning figure. Always check your specific supplier's product density for an order near a delivery weight limit

Stone: What a Pro Checks

Check your specific stone product's density before ordering a large or delivery-weight-sensitive load. Landscape stone density varies more than most bulk materials, roughly 1.2 to 2.2 tons per cubic yard depending on the type.
A decorative top layer over landscape fabric commonly uses about 2-3 in. of depth. A deeper layer isn't automatically better and adds cost without much visual benefit.

Frequently Asked Questions

How many tons of stone do I need?

Multiply your area's volume in cubic yards by the stone's density (commonly 1.2 to 2.2 tons per cubic yard depending on the type). For a 20 ft × 4 ft border at 3 in. deep with the default 1.5 tons/cu yd figure, that works out to about 1.22 tons.

Why does stone density vary so much between products?

Because "landscape stone" covers everything from lightweight, porous lava rock to dense, solid river rock and crushed granite. The material's own density plus how the pieces pack together (angular stone leaves more air gaps than smooth, rounded stone) both affect weight per cubic yard.

What depth should I use for a stone bed or border?

It depends on the application. A decorative top layer over landscape fabric commonly uses 2-3 in., while a drainage or base layer might use more. Check guidance specific to your project rather than assuming one depth fits every use.

Should I order stone by weight or by volume?

Most suppliers price and deliver by the ton, since that's what a delivery truck actually weighs and bills, even though cubic yards are the more intuitive unit for visualizing coverage. This calculator gives both figures so you can order in whichever unit your supplier uses.

What's the difference between this and the Gravel or River Rock calculators?

All three use the same area × depth × density math. They're separated mainly because "gravel," "stone," and "river rock" are searched for as different products with somewhat different typical densities and uses. Use whichever matches the specific material you're buying, and adjust the density input to your product's actual figure if you know it.

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