Sonotube Calculator
Estimate concrete for sonotube deck footings
Common: 8", 10", 12"
Height of each sonotube
Total sonotubes needed
Volume per Tube
—
cu ft
Total Volume
—
cu yd
80 lb Bags
—
bags
Estimated Cost
—
USD
Disclaimer: Results are estimates based on standard formulas. Not a substitute for professional advice from a licensed contractor, engineer, or architect. Verify all calculations before making purchasing or construction decisions.
How to Use This Calculator
Sonotubes are cardboard forms used for deck and porch footings. Our calculator estimates concrete volume and cost per tube.
- Determine frost line depth in your area
- Choose sonotube diameter based on deck load
- Enter tube height and quantity
- Add 10% extra for form variances
Expert Insights
Smart analysis for your Concrete & Masonry project
Slab Thickness Guide
4" for patios, 5-6" for driveways, 6-8" for heavy vehicle loads. Our calculator references your dimensions against ACI 301-20 standards for optimal thickness recommendations.
Bag vs Ready-Mix Analysis
For pours under 1 cubic yard, 80lb bags cost less. Over 3 yards, ready-mix saves 30-50%. Our calculator factors your volume against regional pricing.
Curing & Strength Timeline
Concrete reaches 50% strength in 3 days, 70% in 7 days, and full cure in 28 days. Cold weather? Our calculator flags when heated enclosures are needed.
Calculation Formula
Volume per tube = pi x (D/2/12)^2 x H(ft)
Total = (Volume x Qty) / 27
Concrete Bag Size Comparison
| Bag Size | Bags per Cu Yd | Coverage at 4" | Best For |
|---|---|---|---|
| 40 lb | ~90 bags | ~0.30 sq ft/bag | Small repairs, fence posts |
| 50 lb | ~72 bags | ~0.37 sq ft/bag | Steps, small pads |
| 60 lb | ~60 bags | ~0.45 sq ft/bag | Patios, walkways |
| 80 lb | ~45 bags | ~0.60 sq ft/bag | Driveways, large slabs |
| Ready-Mix | 1 truck load | ~81 sq ft/yard | Projects over 1 cu yd |
Authority References
Our calculations are based on guidelines and standards from these authoritative sources:
- American Concrete Institute (ACI) — ACI 301-20 — Specifications for Structural Concrete. Learn more
- Portland Cement Association (PCA) — Concrete Slab Thickness Guidelines. Learn more
- Quikrete — Concrete Calculator & Mix Guidelines. Learn more
- NRMCA — Concrete in Practice (CIP) Series. Learn more
Frequently Asked Questions
What size sonotube do I need for a deck?
8-12" sonotubes are standard for residential decks. For a 12x12 deck with 6 footings, use 12"x48" sonotubes.
How much concrete per sonotube?
A 12"x48" sonotube holds about 3.14 cubic feet or about 5 bags of 80lb concrete. Plan for 6 bags per tube for safety.