How do I calculate cubic yards?

Cubic yards = (length × width × depth) / 27, where all measurements are in feet (since 1 cubic yard = 3 ft × 3 ft × 3 ft = 27 cubic feet). Example: a space 12 ft long × 6 ft wide × 0.5 ft deep = 36 cubic feet ÷ 27 = 1.33 cubic yards. If measuring in inches: convert to feet first (divide by 12), or use: cubic yards = (L in. × W in. × D in.) / 46,656.

How many cubic yards of concrete do I need for a 10x10 slab?

A standard 4-inch thick concrete slab: 10 ft × 10 ft × (4/12) ft = 10 × 10 × 0.333 = 33.3 cubic feet ÷ 27 = 1.23 cubic yards. Always add 10% for waste and spillage: 1.23 × 1.1 ≈ 1.35 cubic yards. For a 6-inch slab: 10 × 10 × 0.5 = 50 ft³ ÷ 27 = 1.85 cubic yards (order 2.05 with waste).

Cubic Yard Calculator

Enter the length, width, and depth in feet to calculate how many cubic yards of material you need.

How to Calculate Cubic Yards

Formula

Convert depth from inches to feet: depth_ft = depth_in / 12
Calculate cubic feet: ft³ = length × width × depth_ft
Convert to cubic yards: yd³ = ft³ / 27

Common Uses

Concrete slabs and footings
Mulch and topsoil for landscaping
Gravel driveways and paths
Sand for playgrounds and sandboxes

Quick Reference

10 ft × 10 ft at depth	Cubic Yards
2 inches	0.62 yd³
4 inches	1.23 yd³
6 inches	1.85 yd³
12 inches	3.70 yd³

Related Calculators

When You Need Cubic Yard Calculations

A cubic yard is 3 ft × 3 ft × 3 ft = 27 cubic feet, the standard volume unit for bulk materials in the US. Concrete, mulch, topsoil, gravel, sand, and compost are all sold by the cubic yard. To calculate how many cubic yards you need, measure your area length and width in feet, determine depth in feet (e.g., 4 inches = 0.333 ft), multiply all three, then divide by 27. Ordering 10% extra is wise to account for settling and waste.

For irregular areas, break the space into rectangular sections, calculate each section's cubic footage, sum them, then divide the total by 27. A standard concrete slab 10 ft × 12 ft × 4 inches deep requires about 1.48 cubic yards of concrete. A 500 sq ft garden bed with 3 inches of mulch needs about 4.6 cubic yards. Always round up to the nearest quarter yard when ordering.

Common Material Estimates

Project	Area	Depth	Cubic Yards
Garden bed	200 sq ft	3 in	1.85 yds³
Driveway base	400 sq ft	6 in	7.41 yds³
Concrete slab	150 sq ft	4 in	1.85 yds³
Topsoil lawn	1000 sq ft	2 in	6.17 yds³

When and Why Cubic Yards Are Used

The cubic yard is the standard volume unit for bulk materials in residential and commercial construction in the United States. Concrete, fill dirt, topsoil, gravel, mulch, and sand are all ordered and delivered by the cubic yard because the quantities involved in typical projects fall conveniently within this range. One cubic yard equals 27 cubic feet, which is the volume of a cube measuring three feet on each side. To calculate how many cubic yards of material you need, measure the area to be filled in feet, determine the desired depth in feet, multiply length by width by depth to get cubic feet, and divide by 27. For example, covering a 12-foot by 15-foot garden bed with three inches (0.25 feet) of mulch requires 12 times 15 times 0.25 divided by 27, which equals approximately 1.67 cubic yards. Landscapers, contractors, and homeowners use this calculation routinely when ordering from suppliers who charge per yard. Always round up your order to the nearest quarter yard to avoid running short mid-project, and confirm coverage rates with your supplier because material density varies.

Cubic Yard Coverage Reference Table

Material	1 cubic yard covers at 3″ depth	Weight (approx.)
Mulch	108 sq ft	400–800 lb
Topsoil	108 sq ft	2,000–2,700 lb
Gravel	108 sq ft	2,700–3,000 lb
Sand	108 sq ft	2,600–3,000 lb
Concrete	Slab — see mix specs	~4,050 lb