Last updated: October 2026
How to calculate cubic yards
Short answer: measure length × width in feet, convert your depth to feet (inches ÷ 12), multiply the three together, then divide by 27. Add 5–10% extra for waste — it's cheaper than a second delivery.
- Measure the area. Length × width in feet gives you square feet.
- Convert the depth. Depth in inches ÷ 12 = depth in feet. A 4-inch layer is 0.333 ft.
- Multiply. Length × width × depth = cubic feet.
- Divide by 27. That converts cubic feet to cubic yards.
- Add waste. Multiply by 1.10 for a 10% allowance, then round up — suppliers don't sell fractions of a yard precisely.
Example: a 20 × 10 ft driveway at 4 inches deep → 20 × 10 × 0.333 = 66.7 cubic feet → ÷ 27 = 2.47 cubic yards → with 10% waste, order 3 yards.
The cubic yard formula
Short answer: cubic yards = (length × width × depth in feet) ÷ 27. A cubic yard is a cube 3 ft on each side, which is why the divisor is 27 (3 × 3 × 3).
Rectangle: yd³ = (L × W × D) ÷ 27
Circle: yd³ = (π × r² × D) ÷ 27
All measurements must be in feet before you divide. When the depth is in inches, there's a shortcut: square feet × depth in inches ÷ 324 gives cubic yards directly (because 27 × 12 = 324). Read more about the unit on Wikipedia's cubic yard article.
How many cubic yards do I need?
Short answer: most home projects need 1–5 cubic yards — a garden bed about half a yard, a driveway 2–4 yards, a small concrete slab about 2 yards. Use the worked examples below as a sanity check on your own numbers.
Volumes are before the waste allowance — the calculator adds it automatically.
Cubic yard calculator for concrete
Short answer: concrete is ordered by the cubic yard from ready-mix plants — a 12 × 12 ft slab at 4 inches needs 1.85 yards, so you order 2. The calculator above handles the volume; for 80/60/40 lb bag counts use our dedicated page.
Ready-mix concrete is sold by the cubic yard, and short loads (under ~4 yards) often carry a delivery surcharge — so getting the number right matters. For bagged concrete, remember one cubic yard equals 45 eighty-pound bags. Our concrete calculator works out exact bag counts for slabs, walls and footings.
Cubic yard calculator for gravel
Short answer: gravel driveways usually need 3–4 inches of depth — a 20 × 10 ft driveway at 4 inches needs 2.47 cubic yards, roughly 3.5 tons of crushed stone. Order 3 yards.
Gravel is the heaviest common landscaping material at about 1.4 tons per cubic yard, so the tonnage matters as much as the volume — most half-ton pickups can't legally carry a full yard. For driveways and paths with tons and cost built in, see our gravel calculator.
What is a yardage calculator?
Short answer: a yardage calculator is the same thing as a cubic yard calculator — "yardage" is the landscaping trade's word for volume measured in cubic yards. Suppliers, contractors and delivery tickets all talk in yardage.
When a landscape yard asks "how many yards do you need?", they mean cubic yards — not linear yards or square yards. This page is a yardage calculator: it converts your measurements into the cubic-yard figure the supplier needs.
Cubic feet to cubic yards
Short answer: divide cubic feet by 27 to get cubic yards. 54 cubic feet = 2 cubic yards; 100 cubic feet = 3.7 cubic yards.
How much does a cubic yard of material weigh?
Short answer: it depends on the material — mulch is light (~0.3 tons), soil and gravel are heavy (1.1–1.4 tons), and wet concrete is heaviest (~2 tons). Weight matters for delivery: a full yard of gravel can exceed a pickup's payload.
These are averages for estimating — confirm the exact density with your supplier before ordering a full truckload.
Frequently asked questions
What is a yardage calculator?
A yardage calculator is just another name for a cubic yard calculator — “yardage” is the landscaping industry's word for a volume measured in cubic yards. Enter your area and depth and it tells you how many cubic yards of material to order.
How many cubic yards of concrete do I need for a slab?
Multiply slab length × width × (thickness in inches ÷ 12), then divide by 27. A 12 × 12 ft slab at 4 inches thick needs 1.85 cubic yards — order 2 yards to cover waste. For slabs, walls and footings with bag counts, use our
concrete calculator.
Is there a cubic yard concrete calculator for slabs and footings?
Yes — this page handles the volume math for any shape, and our dedicated
concrete calculator goes further with 80, 60 and 40 lb bag counts for slabs, walls and footings.
What is a yard calculator?
“Yard calculator” is shorthand for a cubic yard calculator. If a supplier quotes you “yards” of mulch, soil or gravel, they mean cubic yards — the volume this calculator works out.
What does “cy” mean in a cy calculator?
“Cy” is the common abbreviation for cubic yard, used on delivery tickets and supplier quotes. A cy calculator converts your measurements into cubic yards — exactly what the tool above does.
How many cubic feet are in a cubic yard?
27. A cubic yard is a cube 3 ft × 3 ft × 3 ft, so 3 × 3 × 3 = 27 cubic feet. To convert cubic feet to cubic yards, divide by 27.
How much does a cubic yard of gravel weigh?
About 1.4 tons (2,800 lb) for crushed stone — the density this calculator uses. Pea gravel runs a little lighter and wet gravel a little heavier, so treat it as an estimate and confirm with your supplier.
How much does a cubic yard of mulch weigh?
Roughly 400–600 lb (0.2–0.3 tons) for shredded bark mulch — much lighter than stone, which is why mulch is usually sold by volume rather than weight. This calculator uses 0.3 tons per cubic yard.
How many 80 lb bags of concrete make a cubic yard?
45. An 80 lb bag of concrete mix yields about 0.6 cubic feet, and 27 ÷ 0.6 = 45 bags per cubic yard. For exact bag counts by project, use our
concrete calculator.
Is my project data private?
Completely. Every calculation runs locally in your browser with JavaScript — your measurements are never sent to a server, stored, or tracked.
