Concrete Cost Calculator

Concrete Cost formula

Cubic yards = Length x Width x Thickness (in) / 12 / 27 x (1 + waste %)
Concrete cost = Cubic yards x price per cubic yard
Total = Concrete cost + delivery + short-load fee x yards under 4 + labor rate x square feet
Cost per sq ft = Total / (Length x Width)

Worked example

A 12 x 24 ft driveway 5 in thick: 12 x 24 x (5 / 12) = 120 cubic feet, times 1.1 for waste is 132 cubic feet, or 4.89 cubic yards. At $160 per yard the concrete is $782, plus a $75 delivery fee for $857 in materials.

With a contractor forming and finishing at $6 per square foot, labor on 288 sq ft is $1,728. The total is $2,585, or $8.98 per square foot. Doing the finishing yourself would bring it to about $3 per square foot.

Quick reference

What goes into the price of a slab

The concrete itself is the smaller part of most slab budgets. Ready-mix runs $125 to $200 per cubic yard, and a 4 inch slab uses about 1.36 yards per 100 square feet with waste, so material is roughly $2 to $3 per square foot. Delivery is a flat trip fee, and orders under the truck minimum, usually 3 or 4 yards, pay a short-load charge for each yard the truck runs light.

Labor is where the total grows. Forming, placing rebar or mesh, pouring and finishing usually cost $4 to $8 per square foot for a plain broom finish, more for stamped or colored work. Add the gravel base, rebar, forms and any excavation or demolition. A finished plain slab typically lands at $6 to $10 per square foot.

How to keep the cost down

Order the right amount. Running short means a second delivery fee and a cold joint; ordering far too much wastes money at $150 a yard. Measure the formed area carefully, use 5 to 10 percent waste, and round up to the supplier's quarter-yard increment. If your job is under the truck minimum, ask whether a neighbor or another site nearby can share the load.

Get quotes with the mix strength stated: 3,000 psi is fine for patios and walks, 4,000 psi for driveways in freeze-thaw climates. Pumping adds a few hundred dollars, so leave room for the truck to back up to the forms. Bagged mix at a home center makes sense only below about half a yard, where delivery fees would dominate.

Key facts

• Ready-mix concrete costs about $125 to $200 per cubic yard delivered, depending on region and strength.
• Most suppliers charge a short-load fee of $50 to $150 per missing yard on orders under 3 to 4 yards.
• An installed 4 in slab typically costs $6 to $10 per square foot; the concrete itself is only $2 to $3 of that.
• A cubic yard of concrete covers 81 sq ft at 4 in thick, so a yard of ready-mix at $150 is about $1.85 per square foot in material.
• Bagged concrete costs 2 to 3 times as much per yard as ready-mix, but avoids the delivery and short-load fees on small jobs.

Frequently asked questions

Sources and references

• •CIP 31 Ordering Ready Mixed Concrete (NRMCA)
• •QUIKRETE quantity calculator (bags per slab) (Quikrete)
• •QUIKRETE Concrete Mix No. 1101 product data sheet (Quikrete)