Cubic Yards vs. Cubic Feet (and Cubic Metres) Explained
1 yd³ = 27 ft³ = 0.7646 m³. Convert all dimensions to the same unit before multiplying.
By the TrueSquare team · Updated
Why 27?
A yard is 3 ft, so a cubic yard is a cube 3 ft long, 3 ft wide and 3 ft high: 3 × 3 × 3 = 27 ft³. People often assume it is 9 or 3 because a square yard is 9 ft² and a yard is 3 ft — volume adds a third dimension.
Key conversions
These factors follow from the exact definitions 1 in = 25.4 mm and 1 yd = 0.9144 m.
| From | To | Multiply by |
|---|---|---|
| cubic feet | cubic yards | ÷ 27 (0.037037) |
| cubic yards | cubic feet | 27 |
| cubic yards | cubic metres | 0.764555 |
| cubic metres | cubic yards | 1.30795 |
| cubic metres | litres | 1,000 |
| cubic feet | litres | 28.3168 |
The classic mistake: mixing feet and inches
Area is usually measured in feet but depth in inches. Multiplying 10 ft × 10 ft × 4 in gives 400 — which is neither cubic feet nor cubic yards. Convert the depth first: 4 in ÷ 12 = 0.333 ft, so the volume is 33.3 ft³, or 1.23 yd³.
Quick reference: coverage of one cubic yard
| Depth | Area covered |
|---|---|
| 1 in | 324 ft² |
| 2 in | 162 ft² |
| 3 in | 108 ft² |
| 4 in | 81 ft² |
| 6 in | 54 ft² |
From volume to bags
Bagged materials are sold by volume (mulch, potting mix, some soils) or by weight with a stated yield (concrete, mortar). Divide the cubic feet you need by the volume per bag:
| Bag size | Bags per cubic yard | Bags per cubic metre |
|---|---|---|
| 0.5 ft³ | 54 | ≈ 70.6 |
| 1 ft³ | 27 | ≈ 35.3 |
| 2 ft³ | 13.5 | ≈ 17.7 |
| 3 ft³ | 9 | ≈ 11.8 |
| 40 L | ≈ 19.1 | 25 |
From volume to weight
Quarries and landscape yards often sell by the ton or tonne, so you need the material's bulk density. Density varies with moisture, particle size and how tightly the material is packed, so treat general figures as rough and ask your supplier for theirs.
Weight = volume × bulk density| Material | Commonly cited bulk density | Per cubic yard (approx.) |
|---|---|---|
| Crushed stone | ≈ 100–110 lb/ft³ (1,600–1,760 kg/m³) | 1.35–1.5 US tons |
| Sand | ≈ 90–110 lb/ft³ (1,450–1,760 kg/m³) | 1.2–1.5 US tons |
| Topsoil (moist) | ≈ 70–100 lb/ft³ (1,100–1,600 kg/m³) | 0.95–1.35 US tons |
| Fresh concrete | ≈ 145–150 lb/ft³ (≈ 2,400 kg/m³) | ≈ 2 US tons |
| Bark mulch | ≈ 15–30 lb/ft³ (240–480 kg/m³) | 0.2–0.4 US tons |
Worked example with mixed units
- A path 30 ft long and 3 ft wide needs 3 in of gravel.
- Depth: 3 ÷ 12 = 0.25 ft, so volume = 30 × 3 × 0.25 = 22.5 ft³.
- Cubic yards: 22.5 ÷ 27 = 0.83 yd³. Cubic metres: 0.83 × 0.7646 = 0.64 m³.
- Weight at 105 lb/ft³: 22.5 × 105 = 2,363 lb ≈ 1.2 US tons.
Sources
- NIST — Unit conversion (SI and US customary units)
- NIST Special Publication 811 — Guide for the Use of the SI
This guide is general information, not professional advice. See our disclaimer.