Cement Yard Calculator

Calculate your concrete volume in cubic yards, needed bags, and cubic feet instantly—free and online.

  • 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 Cement Yard Calculator takes your slab length, width and thickness, then instantly shows the total concrete in cubic feet, converts that to cubic yards, and tells you how many 80‑lb bags you’ll need (each bag ≈ 0.6 ft³). Why it matters: Knowing the exact volume prevents over‑ordering, saves money, and ensures you have enough material to finish the pour. How to read the results: 1 cubic yard = 27 cubic feet, so the yard figure is the larger unit for ordering, while the bag count tells you how many bags to purchase. Use the cubic‑feet number for precise mix‑ratio calculations.

Pro tips

  • Add a 5‑10% waste allowance to the bag total.
  • Round up the bag count to the next whole bag.
  • Order one extra bag to cover unexpected spills.
  • Double‑check thickness conversion from inches to feet.

Real-life examples

  • A homeowner pouring a 4 × 8 ft patio.
  • A contractor estimating concrete for a 10 × 20 ft driveway.
  • A DIYer planning a 2‑inch thick garage floor slab.

Case study

John needed concrete for a 12 × 15 ft patio at 4 in thickness. Using the calculator he saw he required 2.2 cubic yards, which translated to 61 bags. He ordered 62 bags, avoided a costly short‑fall, and completed the patio on schedule.

Frequently asked questions

How many 80‑lb bags do I need for a 10 × 12 ft slab 6 in thick?
Enter the dimensions; the calculator will convert the volume to cubic feet, divide by 0.6 ft³ per bag, and round up to the nearest whole bag.
What is the difference between cubic yards and cubic feet?
One cubic yard equals 27 cubic feet; yards are used for bulk ordering, feet for precise mix calculations.
Do I need to include a waste factor?
Yes, add 5‑10 % to the bag count to cover spillage and uneven subgrade.
Can I use the calculator for a circular area?
The tool is for rectangular footprints; for circles calculate area first (πr²) and enter the equivalent length and width.
Is the calculator free to use?
Yes, it’s instant, online, and requires no sign‑up.