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Concrete, Masonry & Stone

Stone Calculator

Work out how much decorative or landscape stone you need by area and depth, in the tons and cubic yards a stone yard quotes.

Your measurements

Each field carries its own units, so you can mix feet and inches.

Area to cover
2 in reads as a decorative layer. 3–4 in covers the ground properly and resists scuffing.
Stone
Lava rock weighs roughly a third of river rock for the same volume.
Override with the figure on your supplier’s spec sheet if you have it.
Covers settling, spillage and uneven ground.

Your result

Sample values

3.67

Cubic yards

99.0

Cubic feet

4.95

Tons

9,900

Pounds

Includes a 10% waste allowance.

What to order

Sold as Quantity
Bulk, by the ton 4.95 tons
Bulk, by the yard 3.67 yd³
0.5 ft³ bags 198 bags
1 ton bulk bags 5 bags

How to use this calculator

Measure the area you want covered and the depth of stone you want once it has settled. For a bed that is not a simple rectangle, split it into rectangles, run each separately and add the results.

Pick the stone type so the weight conversion uses a sensible density, or enter your supplier’s figure directly. Density is what turns a volume into the tonnage a quarry will actually sell you, and it varies more between products than people expect.

Formula

Volume = Length × Width × Depth

Weight = Volume × Density

Tons = Weight ÷ 2,000

Depth
converted to feet before multiplying
Density
pounds per cubic foot for the chosen stone

The waste allowance is applied to the volume before the weight conversion.

Worked example

A 30 ft by 12 ft border bed, 3 in of river rock, 10% waste.

  1. 30 ft × 12 ft = 360 ft² of bed
  2. 3 in ÷ 12 = 0.25 ft of depth
  3. 360 ft² × 0.25 ft = 90 ft³
  4. 90 ft³ × 1.10 = 99 ft³ with waste
  5. 99 ft³ ÷ 27 = 3.67 yd³
  6. 99 ft³ × 100 lb/ft³ = 9,900 lb, or 4.95 tons

3.67 cubic yards, about 4.95 tons

Understanding your results

The same quantity appears four ways because suppliers do not agree on how to sell stone. Landscape yards usually price by the cubic yard, quarries by the ton, and big box stores by the bag. Take whichever figure matches how you are buying.

Tonnage is the softer number. Damp stone weighs more than dry, and a loose delivered pile takes more volume than the same stone once it is raked out and walked on. Treat the weight as a working figure and the volume as the firmer one.

Questions

About this calculator

Ask something else

Two inches is enough to read as a finished surface over landscape fabric. Three to four inches covers the ground properly, hides the fabric at the edges and holds up to being walked on. Deeper than four inches is usually wasted unless you are filling a hollow.

It slows weeds coming up through the stone and stops the stone working down into soft ground, which is the more useful job. It will not stop seeds that land on top of the stone, so it delays rather than prevents weeding.

River rock is solid stone at roughly 100 lb per cubic foot. Lava rock is full of gas voids and comes in around 35 lb. For the same coverage you will order a similar volume but a very different tonnage, which matters if you are paying by weight or carrying it by hand.

You can, but measure the depth you are adding rather than the total. If the old layer is thin, contaminated with soil or full of weed roots, it is usually worth raking out first — new stone over a dirty base goes muddy from underneath within a season.

Keep going

All Concrete, Masonry & Stone tools
Estimates, not specifications. Results are based on the values you enter and on typical material properties. Densities, coverage rates and product sizes vary between suppliers, so confirm quantities against your supplier's data before ordering. Structural work must be signed off by a qualified professional and meet your local building code.