Gravel Calculator

Use this free gravel calculator to estimate how many cubic yards and tons of rock you need for your driveway, patio, or landscaping project.

How to Calculate Gravel for Driveways and Patios

Figuring out the right amount of rock for your project starts with getting accurate measurements of your site. The math is straightforward, but making a mistake with your depth in inches can leave you short on materials on delivery day.

To find your total square footage, measure the length and width of the area in feet. If your driveway has curves, break it down into smaller squares or rectangles, find the area for each, and add them up.

Once you have the total area, you need to factor in the depth. Because bulk suppliers sell construction aggregate by volume, you have to convert your depth from inches into feet. You do this by dividing your inch depth by 12.

Example Calculation:

If you want to build a 10 ft by 10 ft patio area with a 3-inch rock layer:

• 10 x 10 = 100 square feet.
• 3 inches ÷ 12 = 0.25 feet.
• 100 x 0.25 = 25 cubic feet.
• 25 ÷ 27 = 0.92 cubic yards.

Always round up your final number. When you run a plate compactor over fresh stone, it settles. Ordering 10% extra ensures you don’t run out of material during subgrade preparation.

How Deep Should a Gravel Base Be?

The biggest mistake homeowners make is pouring rock too thin. The thickness of your base layer entirely depends on the weight it needs to support and the condition of the soil underneath.

If your dirt base is soft or stays wet, the rock will just sink into the mud over time unless you lay down a heavy-duty landscaping fabric first.

Recommended Depths by Project Type

• Standard Driveways: You need a minimum of 4 to 6 inches of compacted stone to support heavy vehicles. If you park heavy equipment or RVs, dig down 8 to 10 inches.
• Walkways and Pathways: Because these only see light foot traffic, a 2 to 3-inch layer is plenty.
• Patio Base under Pavers: Plan for 4 inches of crushed stone base, topped with 1 inch of leveling sand.
• French Drains: Pipe trenches usually require 2 inches of bedding stone below the pipe and at least 3 to 4 inches of backfill rock on top for proper water drainage.

Common Types of Landscape Rock

Not all rocks do the same job. Picking the wrong stone can ruin a project, even if your volume calculations are correct.

Crusher Run (Quarry Process): This is a mix of angular crushed stone and stone dust. When you wet it and tamp it down, the dust acts like cement. It locks the stones together to create a rock-hard, flat surface. This is the absolute best choice for a driveway base or paver foundation.

Pea Gravel: These are small, smooth, rounded stones. They look great in flower beds and fire pit areas, but they never lock together. If you drive a car over a thick layer of pea gravel, your tires will sink and push the rocks everywhere. Never use it for driveways unless you install a plastic stabilizing grid first.

57 Stone (3/4 Inch Clean): This is crushed rock with all the fine dust washed out. Because there is no dust to fill the gaps, water flows right through it. This makes it the industry standard for French drains, retaining wall backfill, and septic fields.

Ordering Material: Cubic Yards vs. Tons

When you call a local quarry or materials yard for a bulk delivery, they will ask you how much you need in either yards or tons.

A cubic yard is a measurement of volume (how much space the material takes up). A ton is a measurement of physical weight.

Most landscaping yards sell standard crushed stone and topsoil by the cubic yard. However, quarries often weigh their dump trucks on a giant scale before they leave the yard, so they sell by the ton.

The standard conversion rate in the construction industry is 1.4 tons for every 1 cubic yard of standard gravel. If you use our gravel yardage calculator above, it automatically handles this exact conversion for you so you can give the dispatcher the correct number, no matter which unit they use.

Estimating Gravel Costs and Delivery Fees

When budgeting for your project, the cost of the material is only half the equation. Standard crushed stone typically ranges from $30 to $50 per ton, while decorative rocks like river rock or marble chips can cost upwards of $100 per ton.

However, bulk delivery fees often catch homeowners by surprise. Most quarries charge a flat freight fee or an hourly rate for the dump truck, which can add $50 to $150 to your final bill depending on how far you live from the yard. If your project is very small (under 1 cubic yard), buying individual 50-pound bags from a big-box store might actually be cheaper than paying the minimum delivery charge for a bulk truck.

For reference, it takes about 56 fifty-pound bags to make one cubic yard of gravel. If your project requires less than half a yard (about 25 bags), heading to the hardware store is usually the cheaper route.