Concrete Estimator for Contractors

How Concrete Contractors Price a Pour

Start with volume in cubic feet, then convert to cubic yards. The standard conversion is 27 cubic feet in one cubic yard. That ratio is printed in ready mix literature and on most pre-mix bag charts.

For a flat slab, multiply length times width times depth in feet. If you measure depth in inches, divide by 12 first. A 10 by 20 patio at 4 inches thick is 10 × 20 × 0.333 = 66.7 cubic feet, or about 2.47 cubic yards.

Footings use the same math on the trench cross section. Run length down the footing line, width across the trench, and depth to bottom of footing. Add footing segments together on complex foundations.

Post holes are cylinders. Count the holes, multiply pi times radius squared times depth in feet.

Use the diameter you will drill, not the post size. You may want to round up by one hole worth of concrete on a row of posts.

Ready mix is priced per cubic yard delivered. Enter what your local plant quoted you, not a number from the internet.

Short loads and pump fees sit outside this calculator. Add them as a materials line in your proposal.

Bag math is for small pours, patches, and stair repairs. Yields are printed on the bag.

A common 60 lb bag might list about 0.45 cubic feet and an 80 lb bag about 0.6 cubic feet. Change those fields to match the SKU you stock.

Order whole bags or whole yards. The tool rounds bag counts up so you do not come up short at the edge. Waste from over dig and spill belongs in your margin or a small waste factor, not hidden inside a fake average price.

Labor hours per cubic yard should come from your last pours. A simple broom finish slab might run faster than formed steps with rebar ties. Enter your own hours per yard for each job type you sell.

Rebar, wire mesh, vapor barrier, and forming lumber belong in materials. The estimator has one allowance line for steel and accessories. Split them on the invoice if your client asks for detail.

Profit margin is the share of the bid that pays trucks, insurance, and your salary after direct costs. The suggested bid divides subtotal by one minus margin percent. That matches setting a target profit on the final price.

On a phone in the driveway, run slab math before you promise a start date. If the homeowner only has budget for half the square footage, you want to know that before you sink forming labor.

Cure time and weather rules affect schedule, not cubic yards. Still mention them in the proposal so the client knows why you picked a pour window.

When the general contractor asks how you estimated concrete, show length, width, depth, and the 27 conversion. Transparency wins rework disputes later.

Keep a note on past jobs with yards poured, crew hours, and pump use. When this calculator matches those notes, your defaults are calibrated. When it diverges, fix the defaults before the next estimate.

This tool does not replace a site visit. Verify soil, access, and underground lines before you sign. Use the math here to avoid underbidding while you are still in the truck.

Stamped and colored flatwork adds labor outside cubic yards. Price those finishes as extra hours or a flat line so the pour math stays honest.

Cold weather blankets and additives belong in materials when you pour below forty degrees. Track what the plant charged last winter and plug that into your yard price field.

Pump day minimums from the ready mix plant are not in this form. Add the pump quote as a separate proposal line when the truck cannot reach the forms.