Concrete Slab Quote Calculator

Get an instant, free quote for your concrete slab—enter dimensions and price to see cubic yards, cost, bags needed, and cubic feet.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter length, width, and thickness of the slab.
  2. Input the price per cubic yard of concrete.
  3. Click Calculate to view cubic yards, estimated cost, required bags, and cubic feet.

Concrete Slab Quote Calculator instantly turns your slab dimensions and material price into the numbers you need to budget and order. Enter length, width, thickness, and the price per cubic yard; the tool returns total cubic yards, estimated cost, required 80‑lb bags, and cubic feet. Knowing the cubic yards tells you how much concrete the truck will deliver, while the bag count helps you plan for any DIY mixing or supplemental mix. The cost estimate lets you compare suppliers before you commit. Each bag covers about 0.6 ft³, so the calculator divides the total cubic feet by that factor to give a realistic bag total. Use the results to add a 5‑10 % waste allowance, verify your order, and avoid costly over‑or under‑purchasing.

Pro tips

  • Add a 5‑10% waste allowance to the cubic yard total to cover spillage and variations.
  • Round up the bag count; you can’t purchase a fraction of a bag.
  • Order concrete a day before the pour to ensure fresh mix and avoid delays.
  • Double‑check thickness conversions (inches to feet) before entering data.

Real-life examples

  • A homeowner planning a 12‑ft by 20‑ft patio needs to know how many bags to buy.
  • A contractor estimating material for a garage floor wants an instant cost breakdown.
  • A landscaper quoting a client for a new walk‑way slab needs accurate volume and price.

Case study

Mike entered his 15 ft × 30 ft patio dimensions and 4‑in thickness, got 1.85 cubic yards, $210 estimate, and 10 bags. He added 8% waste, ordered 12 bags, and completed the pour on budget without last‑minute trips.

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Frequently asked questions

How do I convert slab thickness from inches to feet?
Divide the thickness in inches by 12; the calculator does this automatically when you enter inches.
Why does the bag count not match the exact volume?
Each 80‑lb bag yields about 0.6 ft³, so the result is rounded up to the nearest whole bag.
Should I include a waste factor?
Yes, add 5‑10% extra volume to cover spillage and uneven subgrade.
What if my concrete price is per cubic meter?
Convert cubic meters to cubic yards (1 yd³ ≈ 0.7646 m³) before entering the price.
Can I use the calculator for a sloped slab?
Enter the average thickness; for complex slopes, break the area into rectangles and sum the results.