Landscaping Rock Calculator

Beautifying your outdoor space with landscape rock products will bring enjoyment, low maintenance, and added value to your home. You can mix styles and colors, and use the rocks for gardens, walkways, borders, driveways, and around trees and shrubs. If you decide to design with these products, here is a landscape stone calculator to help you stay in budget and keep your costs down.

Planning your hardscape projects takes some mathematics to get an accurate idea of your needs. Stone vendors sell landscape rock by the cubic yard, which is calculated by the volume of material. Here’s how to determine the volume of your stone:

How to Calculate Landscaping Rock

Compute the volume in square feet by determining these measurements first:

1. The length of your area in feet.

2. The width of your area in feet.

3. The depth of the stone in feet—divide the depth by 12.

The landscape rock formula is as follows:

(Length x width x depth) / 27

This final number is how many cubic yards of material you will need.

Real-World Calculation Example

For example, say you would like to cover a 10 by 10-foot area with 3 inches of pea gravel. Your landscape rock coverage calculator would look like this:

• 10 x 10 = 100

• 3 ÷ 12 = 0.25

• 100 x .25 = 25

• 25 ÷ 27 = 0.93 cubic yards

What if Your Area is a Circle?

Circular areas require a bit more calculation. A circle with height is a cylinder. The volume of a cylinder = (radius x radius) x 3.14 x height in feet.

For a ten-foot circle, your calculator would look like this:

• 10 ÷ 2 = 5

• 5 x 5 = 25

• 25 x 3.14 = 78.5

• 5 x .25 (3 inches of pea gravel, in feet) = 19.625

• 625 ÷ 27 = 0.72 cubic yards

Calculating Landscaping Rock by Weight

If you need to figure out how many tons to buy, multiply your cubic yards by the weight in tons of the material. Some common landscape rock materials weigh as follows:

Sand 1.10 – 1.25 tons (2,200 – 2,500 lb.) per cubic yard

Landscape Gravels 1.20 – 1.35 tons (2,400 – 2,700 lb.) per cubic yard

Washed Gravel 1.35 tons (2,700 lb.) per cubic yard

Washed Limestone 1.20 tons (2,400 lb.) per cubic yard

Limestone Base 1.35 tons (2,700 lb.) per cubic yard

Lava Rock 0.50 – 0.65 tons (1,000 – 1,300 lbs.) per cubic yard

Accurate calculations will save you time and money, whether you are budgeting for a DIY project or checking behind your contractor.