8 × 10 in Sonotubes 4 ft long on 6 in footings need 26.2 cu ft of concrete — 48 × 80-lb bags with 10% extra.
| Per column | 60-lb | 80-lb |
|---|---|---|
| This calculator (geometry) | 8 | 6 |
Maker tables cover the tube only, so they are hidden while a footing is included.
| Bag | Bags | Est. cost |
|---|---|---|
| 40 lb · 0.3 ft³ | 96 | — |
| 50 lb · 0.375 ft³ | 77 | — |
| 60 lb · 0.45 ft³ | 64 | $310 |
| 80 lb · 0.6 ft³ | 48 | $285 |
At these prices a truck becomes cheaper from about 3.25 yd³ (147 bags). Over 1–2 yd³, a truck also saves hours of mixing: plan on 3–4 minutes per bag in a mixer.
Typical U.S. big-box prices checked 2026. Tap any price to enter your store's.
| Length | Cu ft per tube | 80-lb per tube | 60-lb per tube | 80-lb for 8 (+10%) |
|---|---|---|---|---|
| 2 ft | 2.18 | 4 | 5 | 32 |
| 3 ft | 2.73 | 5 | 7 | 40 |
| 4 ft ← | 3.27 | 6 | 8 | 48 |
| 5 ft | 3.82 | 7 | 9 | 56 |
| 6 ft | 4.36 | 8 | 10 | 64 |
| 8 ft | 5.45 | 10 | 13 | 80 |
Round forms are cylinders: area = π × radius². A 10 in tube has a 5 in radius, so π × 5² = 78.5 sq in ÷ 144 = 0.545 sq ft. Multiply by the length in feet for cubic feet.
3.27 cu ft ÷ 0.6 cu ft per 80-lb bag = 5.45, and ÷ 0.45 per 60-lb bag = 7.27. Tube tables round each tube up.
At 1.07 yd³ with waste, ready-mix (about $528 for 1.25 yd³ with fees) still costs more than bags — and a chute fills tubes in minutes.
The full method, material data and tips are on the main sonotube & column concrete calculator page.