square feet to cubic yards calculator

Square feet to cubic yards calculator formula

A square feet to cubic yards calculator needs the depth as well as the area. The formula is cubic yards = area in square feet × (depth in inches ÷ 12) ÷ 27.

The first part, area times depth in feet, gives cubic feet. The division by 27 turns cubic feet into cubic yards. The calculator shows both numbers. The defaults of 100 sq ft and 4 inches give 33.33 cubic feet and 1.235 cubic yards.

Worked examples

Example 1 is a 100 sq ft bed, covered 4 inches deep.

• Depth in feet: 4 ÷ 12 = 0.333
• Cubic feet: 100 × 0.333 = 33.33
• Cubic yards: 33.33 ÷ 27 = 1.235

Example 2 is a 450 sq ft lawn area, covered 3 inches deep.

• Depth in feet: 3 ÷ 12 = 0.25
• Cubic feet: 450 × 0.25 = 112.50
• Cubic yards: 112.5 ÷ 27 = 4.167

For the second job, you would order about 4.2 cubic yards, plus whatever cushion you choose. Suppliers often sell in half or whole yards, so ask what they deliver.

Cubic yards per 100 sq ft

Depth	Cubic feet	Cubic yards
1 in	8.33	0.309
2 in	16.67	0.617
3 in	25.00	0.926
4 in	33.33	1.235
6 in	50.00	1.852
8 in	66.67	2.469
12 in	100.00	3.704

For other areas, scale the number. 300 sq ft at 4 inches is 3 × 1.235 = 3.704 cubic yards.

How far one cubic yard goes

Flip the question and ask how much area a yard covers. One cubic yard is 27 cubic feet, so the area it covers is 27 ÷ depth in feet.

Depth	Area covered by 1 cubic yard
1 in	324 sq ft
2 in	162 sq ft
3 in	108 sq ft
4 in	81 sq ft
6 in	54 sq ft
8 in	40.5 sq ft
12 in	27 sq ft

This is why a bulk bag or a pickup load covers less than you expect. A yard of mulch spread at 3 inches covers 108 sq ft, which is about a 10 × 11 ft bed.

Common uses

• Mulch and bark for beds, usually 2 to 3 inches.
• Topsoil for lawn repair or a new bed, often 4 to 6 inches.
• Gravel for paths, driveways and bases. Use the gravel calculator when you want tons.
• Sand under pavers or in a sandbox.
• Concrete for slabs and pads, where the volume is often ordered by the yard.

If you know the cubic feet already, the cubic feet to cubic yards calculator skips the area step.

How to measure the area

• Rectangles: multiply length by width in feet.
• Circles: multiply 3.14 by the radius squared. A 10 ft diameter circle has a 5 ft radius and covers 78.5 sq ft.
• Triangles: multiply the base by the height, then divide by 2.
• Odd shapes: divide into simple shapes and add them.
• Measure depth in several places, since ground is rarely level.

Common mistakes

• Forgetting the depth and treating the area as a volume. This is the question the calculator exists to fix.
• Entering the depth in feet when the box wants inches. A depth of 4 ft would be 48 in.
• Dividing by 9 instead of 27. Nine is for square feet to square yards.
• Ordering the net amount. Settling and uneven ground use more than you calculate.
• Forgetting that material sold by weight needs a density. See the cubic yard calculator for volumes and the conversion to tons.

Related calculators

For material with a weight, the gravel calculator gives tons. For a general volume, use the cubic yard calculator, and for mulch beds specifically, the mulch calculator.