How to Calculate How Much Stone You Need (The Easy Way)

One of the most common questions we get at Cornerstone Landscape Supply is: “I have a 20-foot driveway, how many tons of stone should I order?”

Ordering too little means paying for a second delivery fee; ordering too much means having a massive pile of rocks sitting in your yard for months. To help you get it “just right,” we’ve put together this simple guide to calculating your landscape materials like a pro.

1. The Golden Formula

Whether you are buying decorative river rock, crushed limestone, or pea gravel, the formula for volume is always the same:

Length (ft) x Width (ft) x Depth (ft) / 27 = Cubic Yards

2. Step-by-Step Breakdown

• Step A: Measure in Feet. If your area is 20 feet long and 10 feet wide, your square footage is 200 sq. ft.
• Step B: Determine Your Depth. This is where most people get stuck.
  • For driveways, you usually want 3 to 4 inches.
  • For garden paths or decorative borders, 2 to 3 inches is standard.
  • Convert to feet: 3 inches is 0.25 feet (3 / 12).
• Step C: Multiply and Divide. * 200 sq. ft. x 0.25 ft depth = 50 cubic feet.
  • 50 / 27 (the number of cubic feet in a yard) = 1.85 Cubic Yards.

3. Converting Yards to Tons

Most stone is sold by the Ton, while soil and mulch are sold by the Cubic Yard.

• The Rule of Thumb: Most crushed stone weighs roughly 2,500 to 2,800 lbs per cubic yard.
• The Easy Math: Multiply your Cubic Yards by 1.4 to get the approximate tonnage.
• Example: 1.85 yards x 1.4 = ~2.6 Tons.

4. Pro Tips for Accurate Ordering

• Don’t Forget the Compaction: If you are building a base for a patio or a driveway, the stone will settle or “compact” when you run a plate compactor over it. Always add 10% extra to account for this settling.
• Irregular Shapes: If your garden bed is a circle or a kidney shape, treat it like a rectangle that covers the widest points, then multiply by 0.8 to compensate for the curves.

Let Us Do the Math For You!

Still feeling a bit shaky on the numbers? Don’t worry. Just bring your measurements (Length and Width) down to Cornerstone Landscape Supply. Our team uses these formulas every day, and we’ll make sure you get exactly what you need to finish the job.

Ready to order? We offer fast, local delivery for all bulk stone orders. Call us at 304-707-0437 to get a quote today!