Cubic Yards Calculator: How to Calculate Volume

This calculator works out the volume of a rectangular space in cubic yards. You enter the length, width, and depth (or height) in feet or inches, and it returns the volume in cubic yards, plus the equivalent in cubic feet and cubic meters. The first result is the cubic yardage, which is what you need for ordering soil, mulch, gravel, or concrete.

Formula

The formula for cubic yards is:

Cubic Yards = (Length × Width × Depth) ÷ 27

Where:

• Length – the longest horizontal dimension of the area, in feet (ft).
• Width – the shorter horizontal dimension, in feet (ft).
• Depth – the vertical dimension (how deep or high), in feet (ft). If you measure it in inches, convert to feet by dividing by 12.
• 27 – the number of cubic feet in one cubic yard (3 ft × 3 ft × 3 ft = 27 ft³).

All three dimensions must be in the same unit before multiplying. If you measure in inches, convert each dimension to feet first (divide by 12). If you measure in yards, you don’t need to divide by 27—just multiply length × width × depth directly.

Worked Example

Using the default values from the calculator: length = 10 ft, width = 10 ft, depth = 6 in.

1. Convert depth to feet: 6 in ÷ 12 = 0.5 ft.
2. Multiply length × width × depth: 10 × 10 × 0.5 = 50 ft³.
3. Divide by 27 to get cubic yards: 50 ÷ 27 = 1.85 yd³ (rounded to two decimals).

The calculator returns 1.85 cubic yards, 50 cubic feet, and 1.42 cubic meters. That’s the volume you’d need to fill a 10×10 ft area to a depth of 6 inches.

Why Use Cubic Yards?

Cubic yards are the standard unit for bulk materials in the United States and Canada. When you order topsoil, compost, mulch, gravel, sand, or concrete, suppliers typically quote prices per cubic yard. A cubic yard is a cube 3 feet on each side—about the size of a washing machine.

Using cubic yards avoids the confusion of mixing units. For example, a bag of mulch might list its volume in cubic feet, but a truckload is measured in cubic yards. Converting between the two is simple: 1 cubic yard = 27 cubic feet. If you know the area in square feet and the desired depth in inches, you can calculate cubic yards directly with the formula: (area in ft² × depth in inches) ÷ 324. The 324 comes from 27 × 12.

How to Measure for a Project

To get an accurate cubic yard estimate, follow these steps:

• Measure the length and width of the area in feet. For irregular shapes, break the area into rectangles and calculate each separately, then add the volumes together.
• Decide on the depth. For mulch, 2–3 inches is common; for gravel under a patio, 4–6 inches; for a garden bed, 6–12 inches.
• Convert all measurements to feet. If you measured in inches, divide by 12. If you measured in yards, keep them as yards.
• Multiply length × width × depth (all in feet) to get cubic feet.
• Divide by 27 to get cubic yards.

For a circular area (like a tree ring), use the formula for a cylinder: π × radius² × depth. Measure the radius in feet, convert depth to feet, then divide by 27. For a triangular area, use 0.5 × base × height × depth, then divide by 27.

Common Mistakes and How to Avoid Them

The most frequent error is mixing units. If you measure length in feet but depth in inches, you must convert the depth to feet first. Another common mistake is forgetting that a cubic yard is 27 cubic feet, not 3. Some people mistakenly divide by 3 (because a yard is 3 feet), which gives an answer nine times too large.

Rounding too early can also cause problems. If you round the cubic feet to a whole number before dividing, you might be off by a fraction of a cubic yard. For large projects, that can mean ordering too little or too much material. Keep at least two decimal places until the final step.

Finally, remember that volume is three-dimensional. A 10×10 ft area at 6 inches deep is 1.85 cubic yards, but the same area at 12 inches deep is 3.70 cubic yards—double the depth means double the volume.

Reading the Results

The calculator gives three outputs: cubic yards, cubic feet, and cubic meters. The cubic yards value is the one you’ll use when ordering from a supplier. If the result is a decimal (e.g., 1.85), you’ll likely need to round up when ordering, because suppliers usually deliver in whole or half-yard increments. For example, 1.85 cubic yards would mean ordering 2 cubic yards to be safe.

Cubic feet is useful if you’re buying bagged material—many bags are sold by the cubic foot (e.g., 0.75 ft³ or 1 ft³). Divide the total cubic feet by the bag volume to get the number of bags needed. Cubic meters is the metric equivalent, used in most countries outside the US.

Keep in mind that this calculator assumes a perfectly rectangular space with uniform depth. Real-world projects often have slight variations—slopes, uneven ground, or irregular shapes. It’s wise to add 5–10% extra to your order to account for settling and waste, especially for materials like mulch or gravel that compact over time.

When Not to Use This Calculator

This calculator works only for rectangular (box-shaped) volumes. For cylinders (like a round planter or a well), use the cylinder formula: π × radius² × height. For cones (like a pile of sand), use (1/3) × π × radius² × height. For irregular shapes, you may need to approximate by breaking the area into smaller rectangles or using a more advanced method.

Also, this calculator gives volume, not weight. Materials have different densities—a cubic yard of topsoil weighs roughly 2,000–2,700 lb, while a cubic yard of mulch weighs about 400–800 lb. If you need to know weight (for truck capacity or structural load), multiply the volume in cubic yards by the material’s density in pounds per cubic yard. That density is not built into this calculator because it varies widely by material and moisture content.

Frequently Asked Questions

How many cubic feet are in a cubic yard?

There are 27 cubic feet in one cubic yard. This comes from 3 feet × 3 feet × 3 feet = 27 cubic feet. To convert cubic yards to cubic feet, multiply by 27. To convert cubic feet to cubic yards, divide by 27.

How do I convert square feet to cubic yards?

Square feet measure area (two dimensions), while cubic yards measure volume (three dimensions). You need a depth to convert. Multiply the area in square feet by the depth in feet to get cubic feet, then divide by 27. For example, 100 ft² at 0.5 ft deep = 50 ft³ = 1.85 yd³.

How many cubic yards do I need for a 10×10 slab?

It depends on the thickness. For a 4-inch-thick slab (common for patios), convert 4 inches to 0.333 ft, then 10×10×0.333 = 33.3 ft³, divided by 27 = 1.23 cubic yards. For 6 inches thick, it’s 1.85 cubic yards. Always add a little extra for waste and uneven subgrade.

What is the difference between a cubic yard and a yard?

A yard is a unit of length (3 feet). A cubic yard is a unit of volume (3 feet × 3 feet × 3 feet = 27 cubic feet). They measure different properties—length versus volume—so you can’t convert directly between them without knowing the other dimensions.

Can I use this calculator for mulch or gravel?

Yes, the volume calculation is the same regardless of material. However, the weight will differ. Mulch is light (about 400–800 lb per cubic yard), while gravel is heavy (about 2,500–3,000 lb per cubic yard). Check with your supplier for the specific weight per cubic yard if you need to know the load weight.

How much does a cubic yard cover?

Coverage depends on depth. One cubic yard covers 324 square feet at 1 inch deep, 162 square feet at 2 inches, 108 square feet at 3 inches, and 81 square feet at 4 inches. Use the formula: coverage (ft²) = 27 / depth (ft). For example, at 3 inches (0.25 ft), 27 / 0.25 = 108 ft².

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in length | Length | ft | 10 | 0
in width | Width | ft | 10 | 0
in depth | Depth | in | 6 | 0
out cubic_yards | Cubic Yards | yd³ | (length * width * (depth / 12)) / 27 | 2
out cubic_feet | Cubic Feet | ft³ | length * width * (depth / 12) | 2
out cubic_meters | Cubic Meters | m³ | (length * width * (depth / 12)) * 0.0283168 | 2