A tank calculator chart is an essential tool for managing liquid inventory in storage tanks. Whether you are monitoring fuel, water, or industrial chemicals, knowing the exact volume based on a dipstick reading is critical for preventing overflows or running empty.
Calculation Formulas
Depending on the shape of your tank, different mathematical formulas are used:
Horizontal Cylinder: This is more complex because the volume doesn't change linearly with depth. We use the circular segment formula:
Area = R² × cos⁻¹((R-h)/R) – (R-h) × √(2Rh – h²)
Real-World Example
Imagine you have a Horizontal Fuel Tank with a diameter of 48 inches and a length of 120 inches. You use a dipstick and find the fuel level is at 12 inches (25% of the total height).
Because the tank is circular, the bottom 25% of height contains less than 25% of the total volume. In this specific case, 12 inches of depth would equal approximately 237 gallons, while the total tank capacity is 940 gallons. Using a tank calculator chart ensures you don't overestimate your remaining supply.
Why Accuracy Matters
For horizontal tanks, a small error in measurement at the midpoint (where the tank is widest) results in a larger volume discrepancy than at the very bottom or top. Regular calibration using our calculator helps maintain accurate records for logistics and safety compliance.
function toggleTankInputs() {
var shape = document.getElementById("tankShape").value;
var dimLabel1 = document.getElementById("dimLabel1");
var dimLabel2 = document.getElementById("dimLabel2");
var widthContainer = document.getElementById("widthContainer");
if (shape === "horizontal") {
dimLabel1.innerText = "Diameter";
dimLabel2.innerText = "Length";
widthContainer.style.display = "none";
} else if (shape === "vertical") {
dimLabel1.innerText = "Diameter";
dimLabel2.innerText = "Total Height";
widthContainer.style.display = "none";
} else if (shape === "rectangular") {
dimLabel1.innerText = "Length";
dimLabel2.innerText = "Total Height";
widthContainer.style.display = "block";
}
}
function calculateTankVolume() {
var shape = document.getElementById("tankShape").value;
var units = document.getElementById("calcUnits").value;
var d1 = parseFloat(document.getElementById("tankDim1").value); // Diameter or Length
var d2 = parseFloat(document.getElementById("tankDim2").value); // Length or Height
var width = parseFloat(document.getElementById("tankWidth").value) || 0;
var fill = parseFloat(document.getElementById("fillLevel").value);
if (isNaN(d1) || isNaN(d2) || isNaN(fill)) {
alert("Please enter valid numbers for all dimensions.");
return;
}
var totalVol = 0;
var currentVol = 0;
var conversionFactor = (units === "inches") ? 231 : 1000; // cubic inches to gal or cm3 to liters
var labels = (units === "inches") ? "Gallons" : "Liters";
var unitStep = (units === "inches") ? "Inches" : "CM";
var maxDepth = (shape === "horizontal") ? d1 : d2;
function getVolAtDepth(h) {
var v = 0;
if (h maxDepth) h = maxDepth;
if (shape === "horizontal") {
var R = d1 / 2;
var L = d2;
var area = (R * R * Math.acos((R – h) / R)) – ((R – h) * Math.sqrt(2 * R * h – (h * h)));
v = (area * L) / conversionFactor;
} else if (shape === "vertical") {
var R = d1 / 2;
v = (Math.PI * R * R * h) / conversionFactor;
} else if (shape === "rectangular") {
v = (d1 * width * h) / conversionFactor;
}
return v;
}
totalVol = getVolAtDepth(maxDepth);
currentVol = getVolAtDepth(fill);
// Update main results
document.getElementById("totalCapacity").innerText = totalVol.toLocaleString(undefined, {maximumFractionDigits: 2});
document.getElementById("currentVolume").innerText = currentVol.toLocaleString(undefined, {maximumFractionDigits: 2});
document.getElementById("remainingVolume").innerText = (totalVol – currentVol).toLocaleString(undefined, {maximumFractionDigits: 2});
document.getElementById("fillPercent").innerText = ((currentVol / totalVol) * 100).toFixed(1);
var unitLabels = document.getElementsByClassName("unitLabel");
for(var i=0; i<unitLabels.length; i++) {
unitLabels[i].innerText = labels;
}
document.getElementById("tankResult").style.display = "block";
// Generate Chart
var chartBody = document.getElementById("chartBody");
chartBody.innerHTML = "";
var increments = 10;
var step = maxDepth / increments;
for (var j = 0; j <= increments; j++) {
var currentH = step * j;
var vAtH = getVolAtDepth(currentH);
var pAtH = (vAtH / totalVol) * 100;
var row = document.createElement("tr");
row.style.borderBottom = "1px solid #eee";
var cell1 = document.createElement("td");
cell1.style.padding = "10px";
cell1.innerText = currentH.toFixed(1) + " " + unitStep;
var cell2 = document.createElement("td");
cell2.style.padding = "10px";
cell2.innerText = vAtH.toLocaleString(undefined, {maximumFractionDigits: 1}) + " " + labels;
var cell3 = document.createElement("td");
cell3.style.padding = "10px";
cell3.innerText = pAtH.toFixed(1) + "%";
row.appendChild(cell1);
row.appendChild(cell2);
row.appendChild(cell3);
chartBody.appendChild(row);
}
document.getElementById("tankChartContainer").style.display = "block";
}