BuildCalc Guides · Math
How Many Cubic Feet in a Cubic Yard?
The conversion that shows up on every concrete, gravel and mulch job. Short answer, the why, and a quick reference table.
The math
A cubic yard is a 3-foot cube. Every dimension is 3 feet:
- 1 yard = 3 feet (linear).
- 1 cubic yard = 3 ft × 3 ft × 3 ft = 27 ft³.
- To convert ft³ to yd³: divide by 27.
- To convert yd³ to ft³: multiply by 27.
Conversion table
Common volumes both ways. Use the inverse direction by reading the table backwards.
| Cubic yards | Cubic feet |
|---|---|
| 0.25 yd³ | 6.75 ft³ |
| 0.5 yd³ | 13.5 ft³ |
| 1 yd³ | 27 ft³ |
| 1.5 yd³ | 40.5 ft³ |
| 2 yd³ | 54 ft³ |
| 3 yd³ | 81 ft³ |
| 5 yd³ | 135 ft³ |
| 10 yd³ | 270 ft³ |
Where this conversion matters
- Concrete — bags are sold by yield in ft³ (an 80 lb bag = 0.6 ft³), but ready-mix is priced and delivered by the yd³. To compare prices you have to convert.
- Mulch — bagged mulch is 2 or 3 ft³ per bag, bulk is yd³ delivered. 1 yd³ = 13.5 bags of 2 ft³ or 9 bags of 3 ft³.
- Gravel and stone — always priced per yd³ delivered, but bag math (0.5 to 1 ft³ per bag) is the same conversion.
- Topsoil and fill — calculations always start in ft³ from length × width × depth, then convert.
Cubic vs. square — don't mix them up
The biggest mistake is using 9 instead of 27. A square yard is 9 sq ft (3 × 3) — but a cubic yard is 27 cu ft (3 × 3 × 3). Square measures area (flat). Cubic measures volume (3D — with depth). Concrete, gravel and mulch are always cubic.
Convert without the math
BuildCalc's Quick Math handles cubic feet ↔ cubic yards ↔ cubic meters ↔ gallons, plus fractional dimensional input for length and depth.
Open Quick Math →FAQ
How do you convert cubic feet to cubic yards?+
Divide cubic feet by 27. Example: a 10 × 10 × 4 inch slab is 100 × 0.333 = 33.3 ft³. Divide by 27 to get 1.23 yd³.
Why is a cubic yard 27 cubic feet, not 9?+
A yard is 3 feet linearly. A cubic yard is a 3 × 3 × 3 ft cube. 3 × 3 × 3 = 27. People often confuse this with square measurement (a square yard is 9 sq ft = 3 × 3) — but cubic measures all three dimensions.
How many cubic feet are in 0.5 yards?+
13.5 cubic feet — half of 27. This is a useful number for small mulch beds, footings or single post holes.
How heavy is a cubic yard of common materials?+
Concrete ~4,050 lb, dry sand ~2,700 lb, wet sand ~3,200 lb, pea gravel ~2,800 lb, crushed stone ~2,700 lb, topsoil ~2,000 lb, mulch ~800 to 1,500 lb depending on moisture. The "1 yard" volume is constant — the weight varies wildly with the material.
How do I figure out yards from length, width and depth?+
Convert depth to feet (inches ÷ 12), multiply length × width × depth in feet for cubic feet, then divide by 27 for cubic yards. A 10 × 12 ft bed at 3 inches of mulch is 10 × 12 × 0.25 = 30 ft³ ÷ 27 = 1.11 yd³.
Why do mulch and gravel get sold in yards but bags of concrete in cubic feet?+
Bulk materials delivered by truck (mulch, gravel, sand, topsoil, ready-mix concrete) are sold by the cubic yard because trucks are sized in yards. Packaged products (bagged concrete, bagged mulch) are sold by cubic feet because each bag yields a small, repeatable amount. The conversion is always ÷27 or ×27.
Related guides
- How many bags of concrete in a yard? — applies the same conversion to bag yields.
- How many bags of mulch in a yard? — for the bagged-vs-bulk decision on landscaping.
- How many square feet in an acre? — the area conversion you need for lot calculations.