Guide
How to use Cubic Yard Calculator
Start with the working tool above. The notes below explain the inputs, method, limitations and checks that matter for this specific task.
- 1. Measure the length and width of the area in feet.
- 2. Measure or choose the depth.
- 3. Enter the three figures; everything converts to feet internally.
- 4. Read the volume in cubic yards, with cubic feet shown for checking.
- 5. Add a waste allowance — usually 5–10% — before ordering.
How it works
One cubic yard is a cube 3 feet on each side, so it holds 3 × 3 × 3 = 27 cubic feet. That single fact powers the whole method: multiply length × width × depth with everything in feet to get cubic feet, then divide by 27 to get cubic yards: cu yd = (L × W × D) ÷ 27. Depth quoted in inches must be divided by 12 first — 6 inches becomes 0.5 ft. For a circle, replace length × width with the area π × r², then multiply by depth and divide by 27 the same way.
Worked examples
A 12 × 12 ft slab area at 6 inches deep
Depth in feet = 6 ÷ 12 = 0.5 ft. Volume = 12 × 12 × 0.5 = 72 cu ft. Cubic yards = 72 ÷ 27 = 2.67 cu yd. A concrete order would sensibly be rounded to 3 yards once waste is included.
A circular mulch bed, 10 ft across and 3 inches deep
Radius = 5 ft, so area = π × 5² = 78.5 sq ft. Depth = 3 ÷ 12 = 0.25 ft. Volume = 78.5 × 0.25 = 19.6 cu ft. Cubic yards = 19.6 ÷ 27 = 0.73 cu yd — about three-quarters of a yard of mulch.
Topsoil to level a 30 × 20 ft yard area at 2 inches
Depth = 2 ÷ 12 = 0.167 ft. Volume = 30 × 20 × 0.167 = 100 cu ft. Cubic yards = 100 ÷ 27 = 3.70 cu yd. Ordering 4 yards covers the rounding and the thin spots every real lawn has.
When this tool is useful
- Ordering ready-mix concrete for slabs and footings
- Buying topsoil or compost to level a garden
- Calculating mulch coverage for beds and borders
- Sizing gravel, sand or crushed stone deliveries
- Estimating excavation spoil for disposal
Shape guidance: rectangles, circles and irregular areas
The depth step never changes; only the area step does. Rectangle: area = length × width. Circle: area = π × radius², with radius as half the diameter. For an L-shaped or irregular space, split it into rectangles, work each out and add the cubic yards. On a slope, use the average depth.
- Rectangle: length × width × depth ÷ 27.
- Circle: π × radius² × depth ÷ 27.
- Triangle: (base × width ÷ 2) × depth ÷ 27.
- Irregular: add several simple shapes together — close enough for ordering, especially with a waste allowance.
Cubic yard conversions worth knowing
Suppliers, bag labels and older plans mix units freely. These equivalents let you translate between them without a second tool.
- 1 cubic yard = 27 cubic feet.
- 1 cubic yard = 46,656 cubic inches.
- 1 cubic yard ≈ 0.765 cubic metres.
- 1 cubic yard ≈ 202 US gallons of volume.
- A standard pickup bed holds roughly 2–3 cubic yards level-full.
Common mistakes to avoid
- Dividing by 9 instead of 27 — 9 converts square feet to square yards; volume needs 27.
- Multiplying feet by inches directly without converting depth to feet first.
- Forgetting that irregular ground means the average depth, not the deepest or shallowest spot, is the right input.
- Ordering the exact figure with no waste margin; trucks and formwork rarely cooperate to the last percent.
- Using a rectangle calculation for a round bed — a circle's area is π × r², not diameter × diameter.
Frequently asked questions
How many cubic feet are in a cubic yard?
Exactly 27, because a cubic yard is 3 ft × 3 ft × 3 ft. That is why every cubic yard calculation divides cubic feet by 27 — it is a conversion, not an approximation.
How do I calculate cubic yards for an irregular area?
Break the shape into rectangles and triangles, calculate each piece and add them. Or measure the total square footage, multiply by depth in feet, and divide by 27.
How much does a cubic yard cover at 4 inches deep?
One cubic yard is 27 cu ft. At 4 inches (0.333 ft) deep it covers 27 ÷ 0.333 ≈ 81 sq ft; at 3 inches, 108 sq ft; at 6 inches, about 54 sq ft.
How many bags equal a cubic yard?
It depends on bag size: a 2 cu ft bag needs 13.5 bags per cubic yard; a 1.5 cu ft bag needs 18. Beyond a yard or two, bulk delivery is usually cheaper.
Should I add extra when ordering concrete?
Yes, 5–10% is the usual allowance for spillage, uneven subgrade and formwork that is not perfectly true. Running short mid-pour is far more expensive than a little leftover material.
How do I convert cubic yards to cubic metres?
Multiply cubic yards by 0.765 (more precisely 0.7646). So 2.67 cu yd ≈ 2.04 m³. For the reverse, divide cubic metres by 0.765.
Bottom line
Every cubic yard problem reduces to three steps: get everything into feet, multiply for cubic feet, divide by 27. Master that, and material orders stop being guesswork.
If the question changes shape, the closest neighbours are Circle Calculator and Feet and Inches Calculator — or browse everything under Construction & DIY.