function toggleInputs() {
var shape = document.getElementById("poolShape").value;
var fieldLength = document.getElementById("field-length");
var fieldWidth = document.getElementById("field-width");
var fieldWidthB = document.getElementById("field-width-b");
var labelLength = document.getElementById("label-length");
var labelWidth = document.getElementById("label-width");
// Reset visibility
fieldLength.style.display = "block";
fieldWidth.style.display = "block";
fieldWidthB.style.display = "none";
if (shape === "rectangular") {
labelLength.innerHTML = "Length (ft):";
labelWidth.innerHTML = "Width (ft):";
} else if (shape === "round") {
labelLength.innerHTML = "Diameter (ft):";
fieldWidth.style.display = "none";
} else if (shape === "oval") {
labelLength.innerHTML = "Longest Length (ft):";
labelWidth.innerHTML = "Widest Width (ft):";
} else if (shape === "kidney") {
labelLength.innerHTML = "Total Length (ft):";
labelWidth.innerHTML = "Width A (ft):";
fieldWidthB.style.display = "block";
}
}
function calculatePoolArea() {
var shape = document.getElementById("poolShape").value;
var l = parseFloat(document.getElementById("inputLength").value);
var w = parseFloat(document.getElementById("inputWidth").value);
var w2 = parseFloat(document.getElementById("inputWidthB").value);
var result = 0;
if (isNaN(l) || (shape !== "round" && isNaN(w)) || (shape === "kidney" && isNaN(w2))) {
alert("Please enter valid numbers for all dimensions.");
return;
}
if (shape === "rectangular") {
result = l * w;
} else if (shape === "round") {
var radius = l / 2;
result = 3.14159 * (radius * radius);
} else if (shape === "oval") {
// Formula for pool surface area (L x W x 0.8 is industry standard for oval)
result = l * w * 0.8;
} else if (shape === "kidney") {
// Formula: (A + B) x L x 0.45 is industry standard for kidney
result = (w + w2) * l * 0.45;
}
var resultDiv = document.getElementById("result-area");
var finalRes = document.getElementById("finalResult");
finalRes.innerHTML = result.toFixed(2) + " sq. ft.";
resultDiv.style.display = "block";
}
Why Calculate Pool Square Footage?
Knowing the exact square footage of your swimming pool surface is essential for proper maintenance. Whether you are a new pool owner or preparing for a seasonal opening, this measurement affects everything from water chemistry to physical upgrades.
1. Chemical Balancing
Chemical dosages are often calculated based on surface area and total gallonage. Without an accurate square footage measurement, you risk over-treating your water, which can lead to skin irritation, or under-treating it, which may result in algae growth.
2. Ordering Pool Covers
When purchasing a solar cover or a winter safety cover, you need the surface area to ensure complete coverage. A cover that is too small will be ineffective, while one that is too large may be difficult to secure or trim properly.
3. Resurfacing and Plastering
If you plan to replaster, paint, or retile your pool, contractors will provide quotes based on the square footage. Using this calculator helps you estimate material costs for pebble-tec, plaster, or pool paint before inviting professionals for a formal bid.
Standard Formulas Used
- Rectangular: Length × Width
- Circular: π × Radius² (or Diameter × Diameter × 0.785)
- Oval: Length × Width × 0.8 (Industry standard multiplier for rounded ends)
- Kidney: (Width A + Width B) × Length × 0.45
Example Calculations
Example 1: The Standard Backyard Pool
A rectangular pool that is 16 feet wide and 32 feet long.
16 x 32 = 512 Square Feet.
Example 2: Large Round Above-Ground Pool
A circular pool with a 24-foot diameter.
Radius = 12. Area = 3.14159 x 12 x 12 = 452.39 Square Feet.
Example 3: Kidney Shaped Pool
A kidney pool 30 feet long, 10 feet wide at one end, and 14 feet wide at the other.
(10 + 14) x 30 x 0.45 = 324 Square Feet.