Cubic Yards, Bags and Tons Explained

What a cubic yard is

A cubic yard is a cube 3 ft on each side. Because 3 x 3 x 3 = 27, one cubic yard holds 27 cubic feet. Bulk landscape materials and ready-mix concrete are sold by the cubic yard, often in half or quarter yard steps. A yard is roughly what a large wheelbarrow carries in about ten trips.

The formula

Cubic yards = length (ft) x width (ft) x depth (in) / 12 / 27.

Dividing the depth by 12 turns inches into feet, so all three measurements share the same unit and the result is in cubic feet. Dividing by 27 turns cubic feet into cubic yards.

Example: a bed 30 ft long and 5 ft wide covered 3 inches deep is 30 x 5 x 3 / 12 = 37.5 cubic feet, and 37.5 / 27 = 1.39 cubic yards.

Coverage of one cubic yard

Flip the formula around and one cubic yard covers 324 square feet divided by the depth in inches:

• 1 inch: 324 square feet.
• 2 inches: 162 square feet.
• 3 inches: 108 square feet.
• 4 inches: 81 square feet.
• 6 inches: 54 square feet.

This chart is a quick way to sanity-check any calculator result. If you are covering 500 square feet at 3 inches, it should be a bit under 5 yards.

Converting to bags

Bagged materials are labeled by volume or weight. Divide the cubic feet you need by the bag size:

• Mulch: usually 2 or 3 cubic feet per bag. 13.5 bags of 2 cubic feet make one yard.
• Topsoil: usually 0.75 or 1 cubic foot per bag. 36 bags of 0.75 cubic feet make one yard.
• Gravel and sand: often 0.5 cubic feet per bag. 54 bags make one yard.
• Concrete mix: sold by weight. An 80 lb bag yields about 0.6 cubic feet, so 45 bags make one yard.

Bags win for small jobs because there is no delivery fee and no pile on the driveway. Once a job needs more than one to three yards, depending on the material, bulk is usually much cheaper.

Converting to tons

Quarries and stone yards often sell gravel, sand and crushed stone by the ton. Multiply cubic yards by the material's weight per yard. Typical figures are about 1.4 tons per yard for gravel and crushed stone, 1.3 to 1.5 for sand, and 1 to 1.4 for topsoil, more when wet. Mulch is light, around 400 to 800 pounds per yard, and is almost always sold by volume.

Ask the supplier which conversion they use, since it varies by material and moisture. The gravel calculator lets you enter any weight per yard.

Compaction and settling

Loose materials take up less space once they are compacted or settle. Gravel bases compacted with a plate compactor and loose topsoil that settles after rain can both shrink 10% to 20%. When the finished depth matters, order that much extra. Concrete does not shrink this way, but ground is never perfectly flat, so add 5% to 10% for a slab.

Calculators for this guide

Results are estimates, not a contractor quote. Check quantities with your supplier before you order, and follow local building codes. Last reviewed 2026-10-12.