How do I calculate cubic yards of concrete?

To calculate cubic yards of concrete: multiply length (ft) × width (ft) × depth (ft), then divide by 27. For example: 10 ft × 10 ft × 0.333 ft (4 inches) = 33.3 cubic feet ÷ 27 = 1.23 cubic yards.

How many cubic yards of concrete for a 20x20 slab?

A 20×20 foot slab at 4 inches thick requires 4.94 cubic yards (before waste). At 6 inches thick, that is 7.41 cubic yards. Always add 10% for waste and spillage when ordering.

What is the minimum order for ready-mix concrete?

Most ready-mix concrete suppliers require a minimum order of 1 cubic yard. Some charge a short-load fee for orders under 3–5 yards. Call your local supplier for minimum order requirements and delivery fees.

How many cubic yards are in a concrete truck?

A standard ready-mix concrete truck holds 8–10 cubic yards. Some trucks can carry up to 11 cubic yards. You can order a partial load, but minimum order requirements and short-load fees may apply.

How do I convert square feet to cubic yards for concrete?

You cannot convert square feet to cubic yards without knowing the thickness. The formula is: cubic yards = (square feet × thickness in feet) ÷ 27. For a 4-inch slab: yd³ = (sq ft × 0.333) ÷ 27.

What is a short-load fee for concrete and how do I avoid it?

A short-load fee is a surcharge most ready-mix plants charge when you order less concrete than their minimum efficient load — typically 5–7 cubic yards, though this varies by plant. Fees range from $30–$75 per yard under the minimum, meaning a 2-yard order that falls 4 yards short of a 6-yard minimum could cost $120–$300 extra. To avoid it: (1) combine your pour with an adjacent project, (2) call multiple suppliers to find the lowest minimum, or (3) switch to bagged concrete for orders under about 2 yards.

What does slump mean when ordering concrete?

Slump is a measure of concrete workability — how much a freshly mixed sample slumps when the cone-shaped mold is removed. It is measured in inches: a 4-inch slump is standard for most residential slabs and walls. Higher slump (5–7 inches) is more fluid and easier to place in tight forms but produces weaker concrete. Lower slump (2–3 inches) is stiffer and stronger but harder to work. Never add water at the job site to increase slump — it reduces the 28-day compressive strength and durability of the finished concrete.

Concrete Yard Calculator — Cubic Yards of Concrete

Converts dimensions to volume for ordering ready-mix concrete or estimating bag quantities.

What Is a Cubic Yard of Concrete?

This concrete yard calculator converts your project dimensions into cubic yards — the standard unit for ordering concrete in the United States. One cubic yard equals 27 cubic feet (3 feet × 3 feet × 3 feet) and at standard concrete density of 145 lb/ft³ weighs approximately 3,915 pounds (about 2 short tons). Ready-mix concrete is priced per cubic yard — typically $110–$165/yd³ delivered — and a standard ready-mix truck carries 8–10 cubic yards.

Getting the cubic yard calculation right is the most important step before calling a supplier. Ordering too little means stopping mid-pour to wait for another truck — the resulting cold joint between the old and new concrete is a structural weak point. Ordering too much wastes $130–$165 per unused yard. A 10% overage is the standard practice to account for uneven subgrade, out-of-square forms, and spillage.

How to Use This Concrete Yard Calculator

This concrete calculator yards tool converts project dimensions directly to cubic yards (CY) — the unit concrete is sold and ordered in. Enter the length, width, and thickness of your slab, wall, or footing and get instant cubic yard results with a 10% waste factor already included. Need to estimate individual bag quantities instead? Use the concrete bag calculator.

How to Calculate Yards of Concrete

Calculating concrete yardage is straightforward once you know the formula. The fundamental approach for how to calculate concrete yards is to multiply your three dimensions together, then divide by 27 (because 1 cubic yard = 27 cubic feet):

Cubic Yards (CY) = (Length ft × Width ft × Depth ft) ÷ 27

Since thickness is usually measured in inches, always convert to feet first by dividing by 12. A 4-inch slab depth = 4 ÷ 12 = 0.333 feet. A 6-inch depth = 0.5 feet.

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Concrete Yardage Examples for Common Projects

For slab-specific estimates with cost breakdowns, see the concrete slab calculator.

10×10 patio slab, 4 in thick: (10 × 10 × 0.333) ÷ 27 = 1.23 yd³
12×20 garage floor, 4 in thick: (12 × 20 × 0.333) ÷ 27 = 2.96 yd³
20×30 driveway, 6 in thick: (20 × 30 × 0.5) ÷ 27 = 11.11 yd³
40 ft footing, 16 in wide, 12 in deep: (40 × 1.333 × 1) ÷ 27 = 1.97 yd³
30 ft basement wall, 8 ft tall, 10 in thick: (30 × 8 × 0.833) ÷ 27 = 7.40 yd³

Always add a 10% waste factor to your final cubic yard figure before calling your supplier. This accounts for uneven subgrade, slightly out-of-square forms, and spillage during the pour.

How Much Does a Yard of Concrete Cost?

In 2025–2026, a cubic yard of ready-mix concrete costs $130–$170 delivered, depending on your region, PSI strength, and any mix additives. Most suppliers also charge a short-load fee of $30–$60 per yard if you order less than 5–7 yards (the threshold varies by plant).

Here is what common residential projects cost for concrete material alone:

10×10 patio (1.23 yd³) — $160–$210 for concrete + short-load fee = roughly $250–$350
12×20 garage floor (2.96 yd³) — $385–$503 for concrete + short-load fee = roughly $450–$625
20×30 driveway (11.11 yd³) — $1,445–$1,890 for concrete (no short-load fee)

These numbers cover only the concrete — labor, forming, finishing, and site prep add $4–$12 per square foot on top. For a detailed cost breakdown including labor, visit our concrete cost calculator.

How to Order Ready-Mix Concrete by the Yard

Ready-mix concrete is ordered by phone or online from a local batch plant. Call at least 24–48 hours ahead of your pour date. Have the following information ready when you call:

Total cubic yards — your calculated amount including the 10% waste factor, rounded up to the nearest half yard
PSI (strength) — 3,000 PSI for most residential applications; 3,500–4,000 PSI for driveways and exposed slabs; 4,000+ PSI for structural and commercial work
Slump — how workable the mix is; 4–5 inch slump is typical for slabs and walls; do not add water on site to increase slump, as it weakens the concrete
Delivery address and pour date and time — allow 60–90 minutes between truck arrivals for large pours
Special requirements — fiber reinforcement, air entrainment (freeze-thaw climates), accelerators (cold weather), or retarders (hot weather)

Sources & References

ASTM C94/C94M: Standard Specification for Ready-Mixed Concrete — ASTM International
ACI 318-19: Building Code Requirements for Structural Concrete — American Concrete Institute
PCA: Design and Control of Concrete Mixtures (16th Edition) — Portland Cement Association

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Concrete Yard Calculator

Concrete Yardage Calculator

The Formula

Common Conversions