Calculate sonotube concrete volume, footing concrete quantity, and concrete bags needed using accurate contractor-grade concrete pier formulas.
Deck footing — 12 in Ø · 48 in depth · 6 tubes typical
| Diameter | Typical Use | Notes |
|---|---|---|
| 8 in | Fence posts, light decks | Check lateral load |
| 10–12 in | Deck footings, pergolas | Common residential choice |
| 14–16 in | Heavy decks, corners | Engineered plans may specify |
| 18–24 in | Pole barns, large piers | Higher volume per hole |
6× 12 in tubes, 48 in deep.
4× 8 in tubes, 36 in deep.
4× 10 in tubes, 42 in deep.
8× 18 in tubes, 48 in deep.
This sonotube calculator is a focused concrete pier calculator for cylindrical forms. For flatwork, use the concrete slab calculator or concrete volume calculator column mode.
Yes. Sonotube is a brand name for fiber forms; contractors often say concrete tube or pier form for the same cylindrical footing.
Eight 12-inch tubes at 4 feet deep total about 1.0 cubic yard net. With 8% waste, plan roughly 1.1 yards or about 50 bags of 80 lb mix.
Some crews pour into augered holes without forms. Volume math is the same cylinder; tubes keep the pier neat and sized.
How we built this calculator: results use the standard volume, area, and coverage formulas shown on this page, with typical U.S. material densities, bag yields, and waste factors that you can override. Written and checked by the YardsCalculator editorial team. Last reviewed: October 2026.
Last updated: May 22, 2026