Calculate the volume of concrete needed for your Sonotube formwork.
Volume: 0 cubic feet Bags Needed: 0
Understanding Sonotube Concrete Calculation
Sonotubes are commonly used as forms for casting cylindrical concrete columns, piers, and other structural elements. Accurately calculating the amount of concrete required is crucial to avoid under-ordering (leading to costly delays and patchwork) or over-ordering (leading to waste). This calculator simplifies the process by determining the concrete volume and estimating the number of standard concrete bags needed.
The Math Behind the Calculation
The calculation involves determining the volume of a cylinder and then converting it to the appropriate units.
Radius: The radius (r) is half of the diameter.
r = Diameter / 2
Volume in Cubic Inches: The volume (V_in^3) of a cylinder is calculated using the formula:
V_in^3 = π * r^2 * Height
where π (pi) is approximately 3.14159.
Volume in Cubic Feet: Since concrete is typically measured and sold in cubic feet (and bag yields are often specified in cubic feet), we convert the volume from cubic inches to cubic feet. There are 1728 cubic inches in 1 cubic foot (12 inches * 12 inches * 12 inches).
V_ft^3 = V_in^3 / 1728
Number of Bags: To estimate the number of concrete bags, we divide the total required volume in cubic feet by the yield per bag. We then round up to the nearest whole bag to ensure sufficient material.
Bags = ceil(V_ft^3 / Concrete Yield per Bag)
The ceil() function means rounding up to the next whole number.
Input Parameters Explained
Sonotube Diameter (inches): The inner diameter of the Sonotube form. Measure across the opening at its widest point.
Sonotube Height (inches): The vertical height of the concrete column you intend to pour within the Sonotube.
Concrete Yield (cubic feet per bag): This is a critical value provided by the concrete manufacturer on the bag. It indicates how much cubic feet of concrete one bag will yield when mixed with the correct amount of water. Common yields for standard bags are:
~0.5 cubic feet for a 60 lb bag
~0.75 cubic feet for an 80 lb bag
~1.0 cubic feet for a 100 lb bag
Always check your specific product for the exact yield.
Tips for Using the Calculator
Ensure your measurements for diameter and height are accurate.
Use the correct concrete yield specified on your chosen concrete bag.
It's often wise to order slightly more concrete than calculated (e.g., an extra bag) to account for spillage, form absorption, or slight variations in form dimensions.
function calculateConcrete() {
var diameterInches = parseFloat(document.getElementById("tubeDiameter").value);
var heightInches = parseFloat(document.getElementById("tubeHeight").value);
var yieldPerBag = parseFloat(document.getElementById("concreteYield").value);
var resultDiv = document.getElementById("result");
var errorMessage = "";
if (isNaN(diameterInches) || diameterInches <= 0) {
errorMessage += "Please enter a valid Sonotube diameter (must be a positive number).";
}
if (isNaN(heightInches) || heightInches <= 0) {
errorMessage += "Please enter a valid Sonotube height (must be a positive number).";
}
if (isNaN(yieldPerBag) || yieldPerBag <= 0) {
errorMessage += "Please enter a valid concrete yield per bag (must be a positive number).";
}
if (errorMessage !== "") {
resultDiv.innerHTML = errorMessage;
resultDiv.style.backgroundColor = "#dc3545"; // Error red
resultDiv.style.boxShadow = "0 2px 10px rgba(220, 53, 69, 0.4)";
return;
}
var radiusInches = diameterInches / 2;
var pi = Math.PI;
var volumeCubicInches = pi * Math.pow(radiusInches, 2) * heightInches;
var volumeCubicFeet = volumeCubicInches / 1728;
var bagsNeeded = Math.ceil(volumeCubicFeet / yieldPerBag);
// Ensure result is displayed with a reasonable precision, especially for volume
var displayVolume = volumeCubicFeet.toFixed(3);
var displayBags = bagsNeeded;
resultDiv.innerHTML = "Volume: " + displayVolume + " cubic feet" +
"Bags Needed: " + displayBags + "";
resultDiv.style.backgroundColor = "var(–success-green)";
resultDiv.style.boxShadow = "0 2px 10px rgba(40, 167, 69, 0.4)";
}