Quikrete Concrete Mix Calculator

Instantly calculate cubic yards, bags of 80‑lb Quikrete, and cubic feet for any slab – free and instant.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter length in feet.
  2. Enter width in feet.
  3. Enter thickness in inches.
  4. Read cubic yards, bags, and cubic feet results.

What it does – The Quikrete Concrete Mix Calculator turns the dimensions of your slab into three practical numbers: total cubic yards of concrete, how many 80‑lb bags you’ll need, and the raw cubic‑foot volume. Why it matters – Ordering the right amount saves money and prevents delays; too few bags stall the pour, too many add unnecessary cost and waste. How to read the results – Cubic feet shows the raw volume of your shape. Divide that by 27 to see cubic yards, the unit most suppliers quote. Multiply cubic feet by 1.667 (the inverse of 0.6 ft³ per bag) to get the bag count; the tool does this for you and rounds up to whole bags. Use the numbers to place an accurate order and keep your project on schedule.

Pro tips

  • Add a 5‑10% waste allowance to the bag total
  • Always round up to the next whole bag
  • Order a few extra bags for future touch‑ups
  • Double‑check that thickness is converted from inches to feet correctly

Real-life examples

  • Building a 12 ft × 12 ft patio 4 in thick
  • Pouring a 10 ft × 20 ft garage floor 6 in thick
  • Repairing an 8 ft × 5 ft walkway 3 in thick

Case study

Sam needed a 10×10 foot patio 4 in thick. He entered the dimensions, got 1.23 cubic yards, 56 bags, and ordered exactly that, avoiding a $150 over‑order and finishing on schedule.

Frequently asked questions

How many 80‑lb bags do I need for a 5‑inch slab?
Enter the length, width and 5 in thickness; the calculator converts the volume and divides by 0.6 ft³ per bag, then rounds up.
Why does the result show cubic yards as well as cubic feet?
Suppliers quote concrete in cubic yards, while cubic feet is the raw volume of your shape; both help you verify the order.
Should I add extra bags for waste?
Yes, add 5‑10% to the bag count to cover spillage and minor mis‑cuts.
Can I use the calculator for steps or stairs?
Yes, just sum the volume of each step (length × width × rise) and enter the total dimensions.
What if my thickness is in centimeters?
Convert centimeters to inches (1 cm ≈ 0.39 in) before entering the thickness.