function calculateCylinderArea() {
var r = parseFloat(document.getElementById('cyl_radius').value);
var h = parseFloat(document.getElementById('cyl_height').value);
var unit = document.getElementById('cyl_unit').value;
var resultBox = document.getElementById('cyl_result_box');
if (isNaN(r) || isNaN(h) || r <= 0 || h <= 0) {
alert('Please enter valid positive numbers for radius and height.');
return;
}
var pi = Math.PI;
// Base Area = 2 * pi * r^2
var baseArea = 2 * pi * Math.pow(r, 2);
// Lateral Area = 2 * pi * r * h
var lateralArea = 2 * pi * r * h;
// Total Area = Base Area + Lateral Area
var totalArea = baseArea + lateralArea;
document.getElementById('res_base_area').innerHTML = baseArea.toFixed(4) + " " + unit + "²";
document.getElementById('res_lateral_area').innerHTML = lateralArea.toFixed(4) + " " + unit + "²";
document.getElementById('res_total_area').innerHTML = totalArea.toFixed(4) + " " + unit + "²";
resultBox.style.display = 'block';
}
How to Calculate the Surface Area of a Cylinder
Calculating the surface area of a cylinder is a fundamental skill in geometry, essential for various real-world applications such as manufacturing, construction, and engineering. A cylinder consists of two main parts: two circular bases (top and bottom) and a curved side (the lateral surface).
The Surface Area Formula
The total surface area of a cylinder is the sum of the areas of its two circular bases and its lateral surface area. The formula is expressed as:
A = 2πr² + 2πrh
Where:
A is the total surface area.
π (Pi) is a mathematical constant approximately equal to 3.14159.
r is the radius of the circular base.
h is the height of the cylinder.
Step-by-Step Calculation
To find the surface area manually, follow these steps:
Find the Area of the Bases: Multiply the square of the radius by π, then multiply by 2 (for the top and bottom circles). Formula: 2 * π * r².
Find the Lateral Surface Area: Imagine "unrolling" the side of the cylinder into a rectangle. The length of this rectangle is the circumference of the circle (2πr) and the height is (h). Formula: 2 * π * r * h.
Add them together: Sum the two results to get the final total surface area.
Practical Example
Suppose you have a cylindrical water tank with a radius of 3 meters and a height of 10 meters. How much paint do you need to cover the entire exterior?
1. Calculate the base area: 2 * 3.14159 * (3²) = 56.548 square meters.
Using this Cylinder Surface Area Calculator eliminates manual calculation errors and provides instant results for complex decimals. Whether you are calculating the material needed for a pipe, the surface area of a soda can, or the outer skin of a silo, this tool ensures precision across various units like centimeters, meters, inches, and feet.