How to Calculate Cubic Yards

A clear, five-step method for finding exactly how much concrete, gravel, mulch, or soil your project needs. Includes the formula, a conversion table, and five worked examples.

Quick Answer

To calculate cubic yards, multiply length by width by depth with every measurement in feet, then divide by 27. One cubic yard equals 27 cubic feet. If a measurement is in inches, divide it by 12 to convert it to feet before you start.

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

Step-by-Step Instructions

Follow these five steps to get an accurate cubic yard figure for any construction, landscaping, or gardening project.

Measure the length and width

Use a measuring tape to record the length and width of your area. Measure in feet where possible to keep the math simple. Our calculator also accepts inches, yards, meters, and centimeters and converts them for you.

Tip: For irregular shapes, divide the area into separate rectangles, measure each one, and add the totals at the end.

Determine the depth or thickness

Decide how deep the material needs to sit. Depth is usually measured in inches and is the value people most often get wrong, so confirm it before ordering. Common project depths:

Concrete slabs and patios: 4 inches
Driveways: 4 to 8 inches
Garden beds: 6 to 12 inches
Mulch: 2 to 3 inches

Convert every measurement to feet

Volume math only works when all three measurements share the same unit. Convert inches to feet by dividing by 12. For example, a 4 inch depth becomes 0.333 feet. Use the table further down for the most common conversions.

Tip: Mixing feet and inches without converting is the single most common cubic yard mistake.

Multiply, then divide by 27

Multiply length by width by depth to get the volume in cubic feet. Then divide by 27, because there are 27 cubic feet in one cubic yard. Enter your numbers in the calculator and this happens instantly.

Add a waste factor and round up

Real projects lose material to spillage, settling, and uneven ground. Add 5 to 10 percent to your final figure, then round up to the nearest quarter yard. For poured concrete, ordering 10 percent extra is standard practice.

Inches to Feet Depth Conversion

Depth is almost always measured in inches, so this is the conversion you will use most. Divide any inch value by 12 to get its decimal feet equivalent.

Depth in inches	Depth in feet	Common use
1 inch	0.083 ft	Paver sand bedding
2 inches	0.167 ft	Light mulch layer
3 inches	0.250 ft	Standard mulch, decorative gravel
4 inches	0.333 ft	Concrete slab, gravel base
5 inches	0.417 ft	Reinforced slab
6 inches	0.500 ft	Driveway base, deep gravel
8 inches	0.667 ft	Heavy driveway, footings
12 inches	1.000 ft	Raised beds, deep footings

Recommended Depth by Material

Choosing the right depth is what separates an accurate order from a costly over or under estimate. Use these typical depths as a starting point, then adjust for your specific conditions.

Material and use	Recommended depth
Concrete patio or slab	4 inches
Concrete driveway	4 to 6 inches
Concrete footings	8 to 12 inches
Gravel base layer	4 to 6 inches
Gravel driveway	4 to 8 inches
Mulch for garden beds	2 to 3 inches
Mulch for weed suppression	3 to 4 inches
Topsoil for a new lawn	4 to 6 inches
Garden soil for planting beds	6 to 12 inches
Sand for a paver base	1 inch

Worked Examples

Five real scenarios that cover rectangles, circles, and irregular shapes. Each one follows the same multiply then divide by 27 method.

Concrete Concrete patio

Project: a 12 ft by 10 ft patio, 4 inches thick.

Depth: 4 in / 12 = 0.333 ft
Volume: 12 x 10 x 0.333 = 40 cubic feet
Cubic yards: 40 / 27 = 1.48 cubic yards

Mulch Garden bed mulch

Project: a 20 ft by 5 ft bed with 3 inches of mulch.

Depth: 3 in / 12 = 0.25 ft
Volume: 20 x 5 x 0.25 = 25 cubic feet
Cubic yards: 25 / 27 = 0.93 cubic yards

Gravel Gravel driveway

Project: a 30 ft by 12 ft driveway with a 4 inch gravel base.

Depth: 4 in / 12 = 0.333 ft
Volume: 30 x 12 x 0.333 = 120 cubic feet
Cubic yards: 120 / 27 = 4.44 cubic yards
With 10 percent waste: order about 5 cubic yards

Circular Round planting area

Project: a circular bed 10 ft across, with a 5 ft radius, 6 inches deep.

Depth: 6 in / 12 = 0.5 ft
Volume: 3.1416 x 5 squared x 0.5 = 39.27 cubic feet
Cubic yards: 39.27 / 27 = 1.45 cubic yards

Shortcut: enter the 10 ft diameter as both length and width, then multiply the result by 0.785.

Irregular L-shaped patio

Project: an L-shape split into a 10 ft by 8 ft section and a 6 ft by 4 ft section, both 4 inches thick.

Section A: 10 x 8 = 80 sq ft
Section B: 6 x 4 = 24 sq ft
Total area: 104 sq ft x 0.333 = 34.67 cubic feet
Cubic yards: 34.67 / 27 = 1.28 cubic yards

Common Mistakes to Avoid

Most cubic yard errors come from a handful of repeat offenders. Watch for these before you place an order.

Mixing units without convertingMeasuring length in feet but depth in inches and forgetting to convert is the top cause of wrong results. Get everything into feet first.
Forgetting to divide by 27Multiplying length, width, and depth gives cubic feet, not cubic yards. The final division by 27 is what converts the answer.
Skipping the waste factorOrdering the exact calculated amount leaves no room for spillage or settling. Add 5 to 10 percent and round up.
Confusing radius and diameterFor circular areas, the formula uses the radius, which is half the diameter. Using the full diameter quadruples your result.
Measuring uneven ground at one pointSloped or dipped surfaces need an average depth taken from several spots, not a single measurement.

Frequently Asked Questions

What is a cubic yard?

A cubic yard is a unit of volume equal to a cube measuring 3 feet on every side. It equals 27 cubic feet, 46,656 cubic inches, or about 0.765 cubic meters.

How many cubic feet are in a cubic yard?

There are 27 cubic feet in one cubic yard. A cubic yard measures 3 feet by 3 feet by 3 feet, and 3 times 3 times 3 equals 27.

What if my area is not rectangular?

Break the area into smaller rectangles, calculate the cubic yards for each section, then add the results. For curved or circular areas, use the formula pi times radius squared times depth.

How do I calculate cubic yards for a circular area?

Multiply pi, or 3.1416, by the radius squared by the depth in feet, then divide by 27. As a shortcut, enter the diameter as both length and width in the calculator, then multiply the result by 0.785.

Can I mix different units of measurement?

Yes. The calculator converts feet, inches, yards, meters, and centimeters automatically. You can enter length in feet, width in meters, and depth in inches in the same calculation.

How do I convert square feet to cubic yards?

Multiply the square footage by the depth in feet to get cubic feet, then divide by 27. Square feet alone cannot become cubic yards because volume always needs a depth.

How much extra material should I order?

Order 5 to 10 percent more than the calculated amount to allow for spillage, compaction, and uneven ground. For poured concrete, many contractors add a full 10 percent.

How much does a cubic yard weigh?

It depends on the material. A cubic yard of dry topsoil weighs roughly 2,000 to 2,700 pounds, gravel about 2,400 to 2,900 pounds, mulch about 400 to 800 pounds, and poured concrete about 3,700 pounds, close to 2 tons.

How many cubic yards fit in a pickup truck?

A full-size pickup holds roughly 2 to 3 cubic yards of light material such as mulch, but only about 1 cubic yard of heavy material such as gravel or wet soil because of weight limits.

How accurate is the calculator?

The calculator is mathematically exact. The accuracy of your final result depends on the precision of your length, width, and depth measurements.

Ready to Calculate?

Plug in your measurements and get an instant, accurate cubic yard result for your project.

Open the Free Calculator