6 pads of 24×24×12 in take 0.89 cubic yards of concrete — 44 × 80-lb bags with 10% extra, or 1 yd³ of ready-mix.
| Bag | Bags | Est. cost |
|---|---|---|
| 40 lb · 0.3 ft³ | 88 | — |
| 50 lb · 0.375 ft³ | 71 | — |
| 60 lb · 0.45 ft³ | 59 | $286 |
| 80 lb · 0.6 ft³ | 44 | $261 |
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. prices checked October 2026. Tap any price to enter your store's.
| Size | Cubic yards | 80-lb bags | 60-lb bags | Bag cost | Ready-mix |
|---|---|---|---|---|---|
| 12×12×12 in | 0.22 | 11 | 15 | $71.17 | $485 |
| 18×18×10 in | 0.42 | 21 | 28 | $136 | $485 |
| 24×24×12 in | 0.89 | 44 | 59 | $261 | $485 |
| 30×30×12 in | 1.39 | 69 | 92 | $409 | $613 |
24 × 24 × 12 = 6,912 cu in per pad, ÷ 1,728 = 4 cu ft. Times 6 pads = 24 cu ft, ÷ 27 = 0.889 yd³.
With 10% extra that is 26.4 cu ft ÷ 0.6 cu ft per 80-lb bag = 44, rounded up to 44 bags.
At 0.98 yd³ with waste this is a bag job — a truck's 1 yd minimum plus fees would cost about $485.
The full method, material data and tips are on the main concrete footing calculator page.