How it works
Each footing is a cylinder: Volume = π × radius² × height. We add up all of them.
Example
Four 12-inch footings, 4 ft deep, total about 0.47 cubic yards (~21 × 80-lb bags).
Concrete Footing Calculator
Work out the concrete for round footings, piers or Sonotube forms — in cubic yards and bags.
- Free
- No sign-up
- Instant results
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Frequently asked questions
- What size Sonotube do I need?
- Match the tube's inside diameter to your footing size (commonly 8–12 in for decks). Enter that diameter and the depth here.