Cubic Yard Calculator

What a Cubic Yard Is

A cubic yard is a cube 3 feet on every side. Because 3 x 3 x 3 is 27, one cubic yard holds 27 cubic feet. It is the standard sales unit for bulk material in the United States, and it is the unit ready mix plants, quarries, mulch yards and topsoil suppliers all quote in.

• 1 cubic yard = 27 cubic feet
• 1 cubic yard = 0.7646 cubic meters
• 1 cubic yard = 46,656 cubic inches
• 1 cubic meter = 1.308 cubic yards

The 46,656 figure is 36 x 36 x 36, which is useful when a supplier quotes a small quantity in cubic inches, and the 0.7646 conversion matters when a specification or an imported product is written in metric.

A worked example

A driveway 40 feet long and 12 feet wide, to be covered with 4 inches of gravel. The depth in feet is 4 divided by 12, which is 0.3333. Volume is 40 x 12 x 0.3333, which is 160 cubic feet. Divide by 27 and the job needs 5.93 cubic yards. Crushed stone compacts, so add 10 to 20 percent and order 7 cubic yards to finish at 4 compacted inches.

The Unit Trap

The most common error in bulk material ordering is multiplying feet by feet by inches. Doing 40 x 12 x 4 gives 1,920, and dividing that by 27 suggests 71 cubic yards for a small driveway, which is more than four truck loads of stone for a job that needs less than one. Always convert every dimension to the same unit before multiplying, and feet is the easiest unit to convert into because the final division by 27 assumes feet.

What Gets Sold by the Cubic Yard

• Ready mix concrete. Sold in quarter yard increments, with a minimum order and a short load fee below it. A standard truck carries 8 to 10 cubic yards.
• Mulch. Bark, hardwood and colored mulch are sold loose by the yard, and a cubic yard replaces about 13.5 of the two cubic foot bags sold at retail.
• Gravel and crushed stone. Often quoted by the ton as well as by the yard. Crushed stone runs about 1.4 tons per cubic yard, pea gravel about 1.35, river rock about 1.3 and crusher run about 1.5.
• Topsoil and compost. Sold by the yard, and weight varies with moisture from roughly 1,700 to 2,400 pounds per cubic yard.
• Sand. Masonry, concrete and play sand all run roughly 1.3 to 1.4 tons per cubic yard.
• Excavated spoil and demolition debris. Dumpsters and haul off are priced by the yard, and material bulks up 20 to 30 percent once it is dug out, so the hole and the pile are not the same volume.

Converting From Other Units

From inches: divide each dimension in inches by 12 to get feet, multiply, divide by 27. Or multiply all three inch dimensions together and divide by 46,656, which gives the same answer in one step.

From meters: multiply the volume in cubic meters by 1.308 to get cubic yards, or divide cubic yards by 1.308 to go the other way. A 10 cubic meter order is 13.08 cubic yards.

From bags: divide the total cubic feet needed by the bag yield. A 2 cubic foot bag of mulch means 13.5 bags to a yard, a 1.5 cubic foot bag means 18 bags, and a 0.5 cubic foot bag of stone means 54 bags. Loose material is almost always cheaper by the yard once the job needs more than about 10 bags, and it saves a great deal of handling.

Coverage by Depth

One cubic yard spread evenly covers 324 square feet at 1 inch deep, because 27 cubic feet divided by 1/12 of a foot is 324. Every other depth is that figure divided by the depth in inches.

These are neat volumes with no allowance for compaction or waste. Mulch and topsoil settle by roughly 10 percent, crushed stone compacts by 15 to 20 percent, and concrete needs 5 to 10 percent for form movement and spillage.

Irregular Shapes

Break an odd shape into rectangles, work out each one separately and add the volumes. For a circle, multiply the radius in feet by itself, multiply by 3.1416 and by the depth in feet, then divide by 27. For a triangle, take half the base times the height for the area, then multiply by depth and divide by 27. For a sloping depth, average the shallow and deep measurements and treat the area as uniform, which is accurate enough for ordering.