Concrete Deck Pier & Sonotube Cylinder Calculator
Calculate exact cubic feet, cubic yards, and 80 lb or 60 lb concrete bags required for cylindrical cardboard Sonotube deck piers, porch columns, and pole barn footings.
Interactive Material & Cost Estimator
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Quick Reference Coverage Chart (Concrete & Masonry)
Instant pre-calculated material estimates for common US residential project sizes before compaction buffer:
| Typical US Project | Area | Depth | Volume | Weight | Store Bags |
|---|---|---|---|---|---|
| 8" Diameter Sonotube × 48" Deep (1 Pier) | 0.35 sq ft cross-section | 48 inches (4 ft) | 0.05 cu yd (1.40 cu ft) | 207 lbs | 2.4 → 3 bags (80 lb) or 4 bags (60 lb) |
| 10" Diameter Sonotube × 48" Deep (1 Pier) | 0.55 sq ft cross-section | 48 inches (4 ft) | 0.08 cu yd (2.18 cu ft) | 323 lbs | 3.7 → 4 bags (80 lb) or 5 bags (60 lb) |
| 12" Diameter Sonotube × 48" Deep (1 Pier) | 0.79 sq ft cross-section | 48 inches (4 ft) | 0.12 cu yd (3.14 cu ft) | 465 lbs | 5.3 → 6 bags (80 lb) or 7 bags (60 lb) |
| 16" Diameter Sonotube × 48" Deep (1 Pier) | 1.40 sq ft cross-section | 48 inches (4 ft) | 0.21 cu yd (5.59 cu ft) | 828 lbs | 9.4 → 10 bags (80 lb) or 13 bags (60 lb) |
| 24" Diameter Commercial Pier × 48" Deep (1 Pier) | 3.14 sq ft cross-section | 48 inches (4 ft) | 0.47 cu yd (12.57 cu ft) | 1,860 lbs | 21 bags (80 lb) or 28 bags (60 lb) |
Engineering Formula & Material Density Constant
To calculate a cylindrical pier in the interactive tool above, click the "Circle" shape tab, enter your Sonotube diameter in feet (e.g., 0.67 ft for 8", 0.83 ft for 10", 1.0 ft for 12", 1.33 ft for 16"), and enter your pier depth/height in inches in the "Desired Depth" box. Multiply the result by your total number of deck piers.
How to Use the Calculator Above for Single or Multiple Sonotube Piers
Click the "Circle" shape tab at the top of the calculator:
- For an 8-inch Sonotube, enter
0.67in Circle Diameter (Feet). - For a 10-inch Sonotube, enter
0.83in Circle Diameter (Feet). - For a 12-inch Sonotube, enter
1.0in Circle Diameter (Feet). - For a 16-inch Sonotube, enter
1.33in Circle Diameter (Feet). - For an 18-inch Sonotube, enter
1.5in Circle Diameter (Feet).
Calculating Multiple Piers at Once: Click the "Total Sq Ft" tab and multiply the cross-sectional area of 1 pier (from our Quick Reference Table above) by your number of piers. For example, for six 12-inch piers ($6 \times 0.785\text{ sq ft}$), enter 4.71 in Total Area (Sq Ft) and 48 in Depth (Inches) to get your entire deck footing order in one click!
US Frost Line Depth Rules & Belled Footing Bases
Under the International Residential Code (IRC R403.1.4), deck and porch piers must extend at least 6 to 12 inches below the local municipal frost line (typically 12" in Florida/Texas, 36" in the Mid-Atlantic/Midwest, and 48" to 60" in Minnesota, Michigan, and New England). If a pier stops above the frost line, freezing soil moisture expands and heaves the deck upward, snapping ledger boards.
If your building inspector requires a flared plastic Bigfoot / Redi-Base bell form or a square concrete footer pad underneath the Sonotube to spread soil bearing load, add 2 to 4 extra 80 lb bags per hole (or calculate the square footer pad separately using our 60 lb vs 80 lb Concrete Slab Calculator).
Frequently Asked Questions
How many 80 lb bags of concrete for a 12-inch by 4-foot Sonotube?
One 12-inch diameter Sonotube measuring 48 inches (4 feet) tall has a volume of 3.14 cubic feet, which requires 5.23 bags (round up to 6 bags) of 80 lb concrete, or 7 bags of 60 lb concrete.
How many 80 lb bags of concrete for a 10-inch by 4-foot Sonotube?
One 10-inch diameter Sonotube measuring 48 inches tall has a volume of 2.18 cubic feet, requiring 3.63 bags (round up to 4 bags) of 80 lb concrete, or 5 bags of 60 lb concrete.
Do you peel the cardboard Sonotube off after the concrete cures?
You only need to strip away the top 6 to 12 inches of cardboard that is visible above the ground after 24 to 48 hours. The buried portion of the wax-treated cardboard tube can remain underground permanently.
What PSI concrete mix is required for deck pier footings?
Most US residential building codes require a minimum compressive strength of 3,000 PSI to 4,000 PSI (such as Quikrete 5000 or standard 4,000 PSI Crack-Resistant Mix) for structural deck piers.