Concrete Estimate Calculator

Instantly calculate concrete volume, cost, bags and cubic feet for your project – free and instant.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter length, width and thickness of the slab.
  2. Enter the price per cubic yard of concrete.
  3. Click Calculate to see volume, cost, bags and cubic feet.

What it does – The Concrete Estimate Calculator takes the length, width and thickness of your slab and instantly tells you how many cubic yards of concrete you need, the estimated material cost, how many 80‑lb bags to order, and the total cubic feet.

Why it matters – Knowing the exact volume prevents over‑ordering (which wastes money) and under‑ordering (which delays the job). The cost estimate lets you budget accurately, and the bag count helps you communicate with suppliers.

How to read the resultsCubic yards is the standard ordering unit; multiply by your price per yard for the Estimated cost. Bags is the number of 80‑lb bags you should purchase, based on 0.6 ft³ per bag. Cubic feet is a quick reference for smaller projects.

Pro tips

  • Add 5‑10% extra for waste
  • Round up bag count to the next whole bag
  • Order a little more yardage to avoid shortfalls
  • Double‑check thickness conversion from inches to feet

Real-life examples

  • Homeowner pouring a 12×24‑ft patio slab 4 in thick
  • Contractor estimating concrete for a 30×40‑ft warehouse floor 6 in thick
  • DIYer calculating material for a 10×10‑ft driveway 5 in thick

Case study

Mike needed a 12×20‑ft patio 4 in thick. Using the calculator he saw he required 2.22 cubic yards, about 37 bags, and a $350 cost, so he ordered exactly that and finished on schedule without excess waste.

Frequently asked questions

How do I convert thickness in inches to feet for the calculator?
Enter the thickness in inches as given; the calculator handles the conversion internally, you don’t need to convert yourself.
Why does the bag count not match the exact volume?
Bag count is based on each 80‑lb bag delivering 0.6 ft³, so the calculator rounds up to the nearest whole bag.
Can I use the calculator for multiple slabs?
Enter the total combined length, width, and thickness of all areas as one rectangular footprint, or run separate calculations and add the results.
What if my concrete price is per cubic meter?
Convert the price to per cubic yard (1 cubic yard = 0.7646 cubic meters) before entering, or use the calculator for volume only and apply your own conversion.
Is the estimate reliable for reinforced concrete?
The volume is accurate for the concrete itself; reinforcement adds weight but not volume, so the cost for mix remains valid.