Lowes Concrete Calculator

Instantly calculate the concrete volume you need—cubic yards, cubic feet, and bag count—for free.

  • 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, cubic feet, and bag estimate

What it does – The Lowes Concrete Calculator takes the length, width and thickness you input and instantly returns three useful numbers: total cubic feet, cubic yards (27 ft³ = 1 yd³), and 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 the slab cures properly.

How to read the results – Cubic feet shows raw volume, cubic yards is the standard ordering unit for delivery trucks, and the bag count tells you how many mixes to purchase. Round up to the next whole bag to avoid shortfalls.

Pro tips

  • Add 5‑10% extra for waste and spillage
  • Round bag count up to the next whole bag
  • Order concrete in full‑yard increments to match truck loads
  • Double‑check thickness conversion from inches to feet

Real-life examples

  • Building a 12 ft × 12 ft patio 4 in thick
  • Pouring a 20 ft × 30 ft garage floor 6 in thick
  • Creating a 8 ft × 10 ft walkway 3 in thick

Case study

Sam needed a 10 × 10 ft patio at 4 in depth. The calculator showed 1.2 yd³, 33.3 ft³ and 56 bags. He ordered 2 yd³ and 60 bags, avoided a costly shortfall, and finished on schedule.

Frequently asked questions

How many 80‑lb bags do I need for a 10 ft × 12 ft slab 5 in thick?
Enter the dimensions; the calculator will convert the volume to cubic feet and divide by 0.6 ft³ per bag, then round up.
What is the difference between cubic feet and cubic yards?
27 ft³ equal 1 yd³; yards are used for delivery sizing while feet give the raw volume.
Do I need to include a waste factor?
Add 5‑10 % to the calculated volume before ordering to cover spillage and uneven subgrade.
Can I use the calculator for concrete footings?
Yes, just input the footing’s length, width and depth; the same conversion applies.
Is the bag count based on 80‑lb bags?
The tool assumes each standard 80‑lb bag yields about 0.6 ft³ of mixed concrete.