This cubic yard calculator converts a length, width, and depth into cubic yards — the unit that concrete, mulch, gravel, topsoil, and fill dirt are sold by. Enter the footprint in feet and the depth in inches, and it returns the volume in cubic yards, cubic feet, and cubic meters.
Whether you are working out yards of concrete for a slab or bags of mulch versus a bulk delivery, the math is the same: convert everything to feet, multiply, and divide by 27. The sections below spell out the formula, common conversions, and how far one cubic yard actually goes at different depths.
How to Calculate Cubic Yards (Formula)
A cubic yard is a cube measuring 3 feet on each side, so it contains 3 × 3 × 3 = 27 cubic feet. To calculate cubic yards from measurements in feet and inches:
cubic yards = (length ft × width ft × (depth in ÷ 12)) ÷ 27
- Step 1: divide the depth in inches by 12 to convert it to feet.
- Step 2: multiply length × width × depth to get cubic feet.
- Step 3: divide by 27 to get cubic yards.
A useful shortcut for coverage: one cubic yard covers 324 square feet at 1 inch deep, so coverage (sq ft) = 324 ÷ depth in inches. For irregular areas, break the shape into rectangles, calculate each one, and add the volumes together.
Cubic Feet to Cubic Yards Conversion Table
Use these conversions when a bag or spec sheet lists cubic feet instead of yards:
- 27 cu ft = 1 cubic yard
- 13.5 cu ft = 0.5 cubic yard
- 9 cu ft = 0.33 cubic yard
- 3 cu ft (large mulch bag) = 0.111 cubic yard, so 9 bags = 1 yard
- 2 cu ft (standard mulch bag) = 0.074 cubic yard, so 13.5 bags = 1 yard
- 0.6 cu ft (60 lb concrete bag) = 0.022 cubic yard, so 45 bags = 1 yard
- 1 cubic yard = 0.765 cubic meters = 201.97 US gallons
Bagged material typically costs 2–3 times more per yard than bulk delivery, so anything over about half a yard is usually cheaper in bulk.
Example: Yards of Concrete for a 12 × 10 ft Slab
Suppose you are pouring a 12 ft × 10 ft patio slab at the standard 4-inch thickness.
Step 1 — depth in feet: 4 ÷ 12 = 0.333 ft. Step 2 — cubic feet: 12 × 10 × 0.333 = 40 cu ft. Step 3 — cubic yards: 40 ÷ 27 = 1.48 yd³.
Order 1.75 yd³ to allow roughly 10% for uneven subgrade and spillage. At $150–$180 per yard delivered, the concrete costs about $265–$315. The same math works for landscaping materials: that identical 120 sq ft footprint needs 1.11 yd³ of mulch at 3 inches deep or 0.74 yd³ of topsoil at 2 inches deep.
Frequently Asked Questions
How do you calculate cubic yards?
Multiply length × width × depth in feet, then divide by 27. If the depth is in inches, divide it by 12 first. For example, a 12 × 10 ft area 4 inches deep is 12 × 10 × 0.333 = 40 cubic feet, and 40 ÷ 27 = 1.48 cubic yards.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in one cubic yard. A yard is 3 feet, so a cubic yard is 3 × 3 × 3 = 27 cubic feet. That equals 13.5 standard 2-cubic-foot mulch bags or nine 3-cubic-foot bags.
How many cubic yards of concrete do I need for a 10x10 slab?
A 10 × 10 ft slab needs 1.23 cubic yards of concrete at 4 inches thick, or 1.85 cubic yards at 6 inches thick. Order about 10% extra — 1.5 yards for the 4-inch slab — to cover uneven ground and spillage.
How much area does a cubic yard cover?
One cubic yard covers 324 square feet at 1 inch deep, 162 sq ft at 2 inches, 108 sq ft at 3 inches, and 81 sq ft at 4 inches. Divide 324 by your depth in inches to get coverage in square feet.
How many wheelbarrows are in a cubic yard?
A cubic yard is about 9–14 wheelbarrow loads: 13.5 loads with a common 2-cubic-foot wheelbarrow, or 9 loads with a larger 3-cubic-foot contractor model. Plan on 14 trips if you heap loads conservatively.