Construction Calculators

How do you calculate cubic yards for a project?

To get cubic yards, measure length × width × depth in feet, then divide by 27. Almost every material estimate on a job site follows this pattern. Concrete, gravel, sand, topsoil and mulch are all sold by the cubic yard in the US, and one cubic yard is a cube 3 ft on each side, so it holds 3 × 3 × 3 = 27 cubic feet.

The volume formula

1. Convert every dimension to feet. Depth is usually given in inches, so divide it by 12.
2. Multiply length × width × depth to get cubic feet.
3. Divide cubic feet by 27 to get cubic yards, or multiply by 0.0283 to get cubic meters.

Worked example: a 12 × 16 ft patio slab, 4 in thick. Depth is 4 ÷ 12 = 0.3333 ft, so the volume is 12 × 16 × 0.3333 = 64 ft³. Then 64 ÷ 27 = 2.37 yd³. Adding 10% for waste and uneven subgrade brings the order to about 2.61 yd³. The concrete volume calculator runs these steps for slabs, footings and columns, and the cubic feet to cubic yards converter handles the last step on its own.

Board feet for lumber

Hardwood and some framing lumber is priced by the board foot, a volume of 144 cubic inches (1 ft × 1 ft × 1 in). Multiply thickness in inches × width in inches × length in feet, then divide by 12. A 2 × 6 that is 10 ft long is 2 × 6 × 10 ÷ 12 = 10 board feet. Board feet are normally figured from nominal dimensions, not the smaller actual size of dressed lumber.

What does a “yard” of concrete or gravel mean?

A “yard” of concrete, gravel, soil or mulch always means a cubic yard: 27 cubic feet, a cube 3 ft on each side. It is a volume, not the square yard (9 ft²) used for carpet and turf, and not the linear yard used for fabric or rope.

To link the two, you need a depth. One cubic yard spread 4 in deep covers 81 ft², which is 9 square yards; spread 2 in deep it covers twice as much. Linear feet work the same way one dimension down: decking, trim and lumber are sold by length, and multiplying the length by the board width in feet gives the area covered. The area converter handles square feet, square yards and square meters once you have that area.

Bags or ready-mix?

Bagged concrete makes sense for small jobs such as fence posts, steps and small pads. Beyond about a cubic yard it becomes heavy work: one cubic yard takes about 45 bags of 80 lb at a typical yield of 0.60 ft³ per bag, or roughly 3,600 lb of dry mix to lift and mix, so a ready-mix truck is usually the practical choice for driveways, larger slabs and footings. Use the concrete calculator to size the pour before you decide.

How much does a cubic yard of gravel, sand or soil weigh?

A cubic yard of gravel typically weighs about 1.4–1.7 US tons, dry sand about 1.2–1.5 tons and topsoil about 1.0–1.3 tons, depending on the material, its grading and how wet it is. For pounds, kilograms and metric tonnes, the weight converter takes over from there.

Suppliers quote bulk materials by the cubic yard but trucks, scales and some quarries work in tons. The conversion depends entirely on the material's density and moisture, so the figures below are typical ranges for dry material, not exact values. Wet sand, clay or saturated gravel can weigh noticeably more. Confirm with your supplier, or use the cubic yards to tons calculator as a starting estimate.

• Gravel and crushed stone: about 1.4–1.7 US tons per cubic yard.
• Sand: about 1.2–1.5 tons per cubic yard when dry.
• Topsoil: about 1.0–1.3 tons per cubic yard, depending on moisture and organic content.
• Normal-weight concrete: about 2 tons per cubic yard, from a density of roughly 145–150 lb per cubic foot.
• Bark mulch and wood chips: roughly 0.2–0.4 tons (400–800 lb) per cubic yard.

Other everyday job-site conversions

• Roofing: shingles are sold by the square, which is 100 ft² of roof surface. Divide the measured roof area in square feet by 100 to get the number of squares.
• Decking, trim and flooring strips: linear feet times board width gives the covered area in square feet.
• Metric plans: ready-mix ordered in cubic meters converts at 1 m³ ≈ 1.308 yd³.

How do cubic yards, cubic feet and cubic meters relate?

One cubic yard is exactly 27 cubic feet, or about 0.7646 cubic meters, and one cubic meter is about 1.308 cubic yards. Every value in the table below follows from the international yard of exactly 0.9144 m, fixed by the 1959 International Yard and Pound Agreement, and the US gallon of exactly 231 in³ in NIST Handbook 44.

These factors matter when plans, suppliers and products use different systems: a structural drawing may specify concrete in cubic meters, the ready-mix plant may batch in cubic yards, and a sealer or curing compound may be sold by the gallon. Convert small volumes with the cubic feet to cubic yards converter, and liquids with the volume converter.

How much extra material should you order?

Order about 5–10% more concrete and 10–15% more gravel or base stone than the calculated volume, and expect mulch and topsoil to settle after they are spread.

An exact volume is the minimum you need, not what you should order. Real jobs lose material to over-excavation, uneven ground, form bulge, spillage and compaction, so estimators add an allowance on top of the calculated volume.

• Concrete: add 5–10%. Running short in the middle of a pour creates a cold joint, which costs far more than a little extra concrete.
• Gravel and base stone: loose aggregate compacts when it is tamped or rolled, so order roughly 10–15% more than the finished depth requires. The same length × width × depth ÷ 27 formula gives the gravel volume for driveways and paths.
• Mulch and topsoil: these settle over the first weeks, so a 3 in layer may end up closer to 2 in. Bagged mulch is often sold in 2 ft³ bags, so one cubic yard equals 13.5 bags.
• Round up to the delivery unit. Ready-mix plants often sell in quarter or half yard increments and may charge a short-load fee for small orders.

Always check your local building code and the product manufacturer's instructions for required slab thickness, reinforcement and base preparation. These calculators estimate quantities; they do not replace an engineer's design.