Sonotube Calculator

The Sonotube Calculator estimates the volume of concrete required to fill cylindrical concrete forms based on diameter, height, and quantity. This calculator is designed to help construction professionals and DIY builders plan their concrete projects with accurate material estimates. Whether you're pouring deck footings, fence posts, or structural columns, this tool provides the information needed to order the right amount of concrete.

Internal diameter of the tube form (1-72 inches)
Total height or depth of the tube form (0.1-50 feet)
Number of tubes to be filled (1-1000)

This calculator provides estimates only. Actual concrete requirements may vary based on site conditions, form tolerances, and waste factors. Contact a concrete professional for accurate project planning.

How This Calculator Works

  1. Enter the diameter of your Sonotube form in inches (the width across the opening).
  2. Enter the height or depth of the tube in feet (how deep or tall the form is).
  3. Specify how many tubes you need to fill for your project.
  4. Click Calculate to see the total concrete volume and number of bags required.

How Concrete Volume Is Calculated

The calculator uses the standard formula for the volume of a cylinder to determine how much concrete each Sonotube requires. This geometric approach provides a reliable estimate for planning concrete deliveries or purchasing bagged mix.

V = π × r² × h

Where:

  • V = Volume in cubic feet
  • π = Pi (approximately 3.14159)
  • r = Radius (diameter ÷ 2, converted to feet)
  • h = Height or depth in feet

The diameter in inches is first converted to feet, then the radius is calculated. After finding the volume in cubic feet, the result is divided by 27 to convert to cubic yards, which is the standard unit for ordering ready-mix concrete. Bag estimates are calculated using industry-standard yield rates: each 60-lb bag yields approximately 0.45 cubic feet, and each 80-lb bag yields approximately 0.60 cubic feet.

These estimates are based on ideal conditions. Consider ordering 5-10% extra concrete to account for spillage, uneven ground, or variations in tube dimensions.

What Your Concrete Volume Means

Your calculated volume tells you how much concrete is needed to fill your specified tubes. This information helps you decide whether to order ready-mix delivery or purchase bagged concrete from a home improvement store.

Common Project Scenarios

Small Projects (Under 1 Cubic Yard): For volumes under 1 cubic yard (27 cubic feet), bagged concrete may be more practical. A standard pickup truck can typically carry 40-50 bags of 60-lb concrete. This option works well for fence posts, small deck footings, or repair work.

Medium Projects (1-3 Cubic Yards): Ready-mix delivery becomes more cost-effective at this volume, though some suppliers have minimum delivery charges. Bagged concrete remains an option if delivery access is limited or for remote locations.

Large Projects (Over 3 Cubic Yards): Ready-mix delivery is typically the most efficient choice. The concrete arrives pre-mixed and ready to pour, saving significant labor compared to mixing dozens of bags by hand.

Common Sonotube Size Volume per Foot of Depth 60-lb Bags per Foot
8" diameter 0.35 ft³ 1 bag
10" diameter 0.55 ft³ 2 bags
12" diameter 0.79 ft³ 2 bags
16" diameter 1.40 ft³ 4 bags
24" diameter 3.14 ft³ 7 bags

Important Consideration

Always verify local building codes for footing requirements. Many jurisdictions specify minimum diameter and depth based on frost lines, soil conditions, and structural load. The calculated volume assumes a perfect cylinder; actual forms may have slight variations that affect the final concrete needed.

For accurate project planning, consider consulting with a concrete supplier or structural engineer, especially for load-bearing applications or projects requiring building permits.

References

  • American Concrete Institute - Concrete Construction Guidelines
  • Portland Cement Association - Concrete Calculator Methods
  • International Code Council - Residential Footing Requirements
  • Quikrete - Concrete Bag Yield Specifications

Calculation logic verified using publicly available standards.

View our Accuracy & Reliability Framework →