Quikrete How Much Do I Need Calculator

Instantly calculate how many cubic yards, bags, and cubic feet of Quikrete you need for any slab—free, no sign-up.

  • 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 the cubic yards, bags, and cubic feet results

What it does – You enter the slab’s length, width, and thickness. The tool converts those dimensions to total cubic feet, then divides by 27 to show cubic yards, and finally divides by 0.6 cf per 80‑lb bag to tell you how many bags to order. Why it matters – Ordering too little means trips back to the store; ordering too much adds unnecessary cost and waste. How to read – The Cubic yards line tells you the volume you’ll pour, Bags is the number of 80‑lb bags to buy (round up), and Cubic feet is a quick sanity check of the raw volume. Use the results to plan delivery, budget, and site preparation.

Pro tips

  • Add 10% extra for spillage and uneven subgrade
  • Round bags up to the next whole bag; you can’t buy partial bags
  • Order bags a day early to ensure delivery slots
  • Double‑check thickness conversion (inches to feet) before entering

Real-life examples

  • Homeowner pouring a 12 ft × 8 ft patio 4 in thick
  • Contractor estimating concrete for a 20 ft × 30 ft garage floor
  • DIYer building a 6 ft × 6 ft garden stepping stone base 3 in thick

Case study

Mike needed a 10 ft × 5 ft, 4‑in slab for his workshop. The calculator showed 0.62 yd³, 28 bags. He ordered 28 bags, avoided a costly second delivery, and finished on schedule.

Frequently asked questions

How do I convert thickness from inches to feet?
Divide the inches by 12 (e.g., 4 in ÷ 12 = 0.33 ft).
Why does the calculator show bags as a decimal?
It reflects the exact volume; always round up to the next whole bag.
Can I use the result for 60‑lb bags?
No, the bag yield (0.6 cf) applies to 80‑lb bags; adjust manually for other sizes.
What if my slab isn’t a perfect rectangle?
Break the area into rectangles, calculate each, then add the results.
Do I need to include reinforcement in the volume?
Reinforcement doesn’t change concrete volume; order based on the concrete alone.