How to calculate cubic yards
cubic yards = (L × W × D in feet) ÷ 27
Example: 12 ft × 10 ft bed, 3 inches of mulch
- Convert depth to feet: 3" ÷ 12 = 0.25 ft
- Multiply: 12 × 10 × 0.25 = 30 cubic feet
- Divide by 27: 30 ÷ 27 = 1.11 cubic yards
- Order: 1.25 yd (about 10% added for settling, a rule of thumb, then rounded up to a quarter yard)
How to calculate board feet
board feet = (T × W × L) ÷ 12
T and W in inches, L in feet
A board foot is a volume unit equal to 144 cubic inches: 1 inch thick, 12 inches wide and 12 inches long, in nominal dimensions (USDA Forest Products Laboratory, Wood Handbook). Standard 2×4×8 = (2 × 4 × 8) ÷ 12 = 5.33 bf. Use nominal dimensions for pricing: lumber is priced by nominal size even though the dried, planed piece you receive is smaller.
Material coverage guide (100 sq ft)
| Depth | Cubic yards | Cubic feet |
|---|---|---|
| 1" | 0.31 | 8.33 |
| 2" | 0.62 | 16.67 |
| 3" | 0.93 | 25.00 |
| 4" | 1.23 | 33.33 |
| 6" | 1.85 | 50.00 |
| 8" | 2.47 | 66.67 |
| 12" | 3.70 | 100.00 |
Common material weights (lbs per cubic yard)
Typical trade figures, not official ones: moisture, grading and the source pit all change them, so use your supplier's figure when weight matters. Tons are short tons of 2,000 lb.
| Material | Lbs / yd³ | Tons / yd³ | Notes |
|---|---|---|---|
| Concrete (mixed) | 4,050 | 2.02 | Poured foundations, slabs |
| Gravel (dry) | 2,800 | 1.40 | Road base, drainage, driveways |
| Gravel (wet) | 3,375 | 1.69 | Heavier when saturated |
| Sand (dry) | 2,700 | 1.35 | Paver base, sandbox |
| Topsoil (dry) | 2,000 | 1.00 | Landscaping, lawns |
| Topsoil (wet) | 3,240 | 1.62 | After rain; heavier to haul |
| Mulch (wood) | 500 | 0.25 | Gardens, playgrounds |
| Compost | 1,100 | 0.55 | Garden amendment |
| Asphalt (compacted) | 3,915 | 1.96 | Pavement, driveways |
| Crushed stone | 2,700 | 1.35 | #57 stone, drainage |
Standard lumber board feet
| Nominal size | Board feet |
|---|---|
| 2×4×8 | 5.33 bf |
| 2×4×10 | 6.67 bf |
| 2×4×12 | 8.00 bf |
| 2×6×8 | 8.00 bf |
| 2×6×12 | 12.00 bf |
| 2×8×12 | 16.00 bf |
| 2×10×12 | 20.00 bf |
| 4×4×8 | 10.67 bf |
| 1×6×8 | 4.00 bf |
How to order materials by the cubic yard without overpaying
Most bulk landscape and construction materials are sold by the cubic yard. The number you punch into the calculator is rarely the number you order, though. Three adjustments turn raw volume into a practical purchase order:
- Add for compaction. Mulch, topsoil, and gravel settle over the first few weeks once rain and foot traffic get to them. How much depends on the material, so ask your supplier and spread a little deeper than the finished depth you want.
- Add for spillage and waste. Any project involving a wheelbarrow or shovel loses some material to slop and overshoot. Concrete pours especially benefit from a small overage — running short mid-pour ruins the slab.
- Round up to the nearest delivery unit. Some suppliers sell in 1-yard increments, others in quarter-yard. There's no point ordering 2.13 cubic yards if the truck only delivers whole yards.
One common rule of thumb, a convention rather than a standard: add about 10% for soil and mulch, 15% for gravel and stone, 5% for concrete. Concrete has a tighter tolerance because the surcharge for return loads is high if you over-order, but stone and soil can be reused or dispersed easily if you're left with extra.
What a dump truck of material actually weighs
Volume is half the story. Weight matters when arranging delivery, planning driveway access, and figuring out whether your local supplier's truck can even bring you what you ordered. The figures below are typical, not official; your own vehicle's payload rating (on the door-jamb label) and your supplier's truck govern.
| Truck type | Cubic yards (volume) | Max weight payload |
|---|---|---|
| Pickup truck (half-ton) | 0.5-1 yd | 1,000 lbs |
| Pickup truck (3/4-ton) | 1-2 yd | 2,000 lbs |
| Single-axle dump truck | 5-7 yd | 14,000 lbs |
| Tandem (tri-axle) dump truck | 10-12 yd | 23,000-26,000 lbs |
| Semi-trailer (live-bottom) | 15-20 yd | 40,000 lbs |
Practical implications: 2 yards of crushed stone weighs about 5,400 lbs at the typical density above, several times what a half-ton pickup is built to carry, and the supplier may refuse to load you that heavy. Conversely, a single-axle dump truck full of mulch (500 lbs/yd) is far below its weight limit and can usually deliver an oversized "heaped" load — get a quote for a heaped vs struck load.
If your driveway is narrow, gated, or has overhead branches, ask about delivery vehicle size before ordering. A loaded tri-axle may not fit down a narrow private drive, and turning around a loaded truck on a residential lot can damage lawns and sewers. Many suppliers offer dump-trailer rentals as an alternative for tight access sites.
Frequently asked questions
How do I calculate cubic yards?
Put every dimension in feet, multiply them together, and divide the product by 27, the number of cubic feet in a cubic yard. For instance, a 12 by 10 foot bed covered 3 inches deep (a quarter of a foot) holds 30 cubic feet, or 1.11 cubic yards. Suppliers' advice is usually to order a little over for settling and uneven ground.
How much concrete do I need for a slab?
Find the slab's volume in cubic yards the same way: a 10 by 10 foot slab 4 inches thick is 1.23 cubic yards. Ready-mix is sold by the yard, so ask the supplier for a delivered price and any small-load charge. Bagged concrete is the alternative for small pours; at a typical 0.45 cu ft per 60 lb bag the same slab takes 75 bags, and your bag's printed yield governs.
How much gravel do I need for a driveway?
Work each layer separately. A 12 by 50 foot drive with 4 inches of base is 7.4 cubic yards, and a 2-inch surface layer on top adds 3.7 more. Layer depths depend on your soil and traffic, so check with a local supplier. At the typical densities listed here, a cubic yard of dry gravel weighs about 1.40 tons, and wet gravel about 1.69.
What's the difference between cubic feet and cubic yards?
A cubic yard is 27 cubic feet (3 ft × 3 ft × 3 ft = 27 cu ft). Landscape and construction materials like mulch, gravel, and concrete are typically sold in cubic yards. Smaller bagged materials are often in cubic feet: 2 cu ft, 3 cu ft bags. To convert: divide cubic feet by 27 to get cubic yards, or multiply cubic yards by 27 to get cubic feet.
How many tons are in a cubic yard?
It depends on the material. Using the typical densities in the table on this page: concrete about 2.02 tons, dry gravel 1.40, wet gravel 1.69, dry topsoil 1.00, sand 1.35 and wood mulch 0.25. These are trade figures, not official ones; moisture and grading change them, so use your supplier's figure when weight matters.
How do I measure an irregular area?
Break it into regular shapes (rectangles, triangles, circles), calculate each separately, then add them up. For L-shaped areas: calculate two rectangles. For round or curved areas: use π × r² for circles. For irregular perimeters, approximate with rectangles or measure the longest and widest dimensions and average them. Irregular jobs usually need a bigger allowance than square ones; how much is a judgment call.
How many cubic feet are in a gallon?
A US gallon is defined as 231 cubic inches, which makes it 0.134 cubic feet; turned around, a cubic foot holds 7.48 gallons and a cubic yard about 202. A cubic meter is 1,000 liters, about 264 US gallons. These come from the NIST definitions, and the Convert tab above does the arithmetic for any amount.