Concrete Cylinder Calculator

Calculate concrete cylinder volume, needed 80‑lb bags and cubic feet instantly – free.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter diameter in inches, height in feet, and quantity.
  2. Click Calculate.
  3. Read cubic yards, cubic feet, and bag count.

What it does – The calculator turns the dimensions of a concrete cylinder (diameter in inches, height in feet) and the number of cylinders into three practical results: total cubic yards for ordering, total cubic feet for on‑site checks, and how many 80‑lb bags of mix you’ll need. Why it matters – Knowing the exact volume prevents over‑ordering, saves money, and ensures you have enough material to finish the job without delays. How to read the numbers – Cubic yards is the industry standard for delivery quotes; cubic feet lets you compare against site capacity; the bag count uses the constant 0.6 ft³ per 80‑lb bag, so divide the cubic‑feet total by 0.6 and round up. You can also adjust the quantity field to see how material needs scale for multiple columns or footings, making planning faster.

Pro tips

  • Add a 10% waste allowance to the bag count.
  • Round up the bag total to the nearest whole bag.
  • Order a little extra to cover spillage.
  • Double‑check diameter conversion from inches to feet when entering height.

Real-life examples

  • Homeowner estimating concrete for a new patio post.
  • Contractor budgeting material for multiple foundation piers.
  • Landscaper planning decorative concrete columns for a garden.

Case study

Sam needed 4 concrete footings 12" diameter, 3 ft deep. The calculator showed 0.31 cubic yards, 10.5 cubic feet, and 18 bags. He ordered 20 bags, avoided a short‑fall, and finished on schedule.

Frequently asked questions

How do I convert the diameter from inches to feet?
Divide the inch measurement by 12; the calculator does it internally, you just enter inches.
Why does the result show cubic yards instead of cubic feet?
Concrete suppliers quote in cubic yards, so the tool converts total cubic feet to yards (1 yard = 27 ft³).
Do I need to include the space between cylinders?
No, the calculator assumes each cylinder is separate; add extra volume manually if they are packed together.
What if I use a different bag size?
The bag count uses the 0.6 ft³ per 80‑lb bag constant; for other sizes, divide the cubic‑feet total by the bag’s yield.
Is the calculator accurate for irregular shapes?
It’s designed for perfect cylinders; for irregular forms use a volume‑by‑weight method or consult an engineer.