function calculatePercentageIncrease() {
var initial = parseFloat(document.getElementById('initialValue').value);
var final = parseFloat(document.getElementById('finalValue').value);
var resultContainer = document.getElementById('resultContainer');
var resultOutput = document.getElementById('resultOutput');
var differenceOutput = document.getElementById('differenceOutput');
if (isNaN(initial) || isNaN(final)) {
alert("Please enter valid numbers in both fields.");
return;
}
if (initial === 0) {
alert("The original value cannot be zero because division by zero is undefined.");
return;
}
var difference = final – initial;
var percentageIncrease = (difference / Math.abs(initial)) * 100;
resultContainer.style.display = "block";
resultOutput.innerText = percentageIncrease.toFixed(2) + "%";
if (difference >= 0) {
differenceOutput.innerText = "This represents an actual increase of " + difference.toLocaleString();
} else {
differenceOutput.innerText = "This represents a decrease of " + Math.abs(difference).toLocaleString();
}
}
How to Calculate Percentage Increase: A Step-by-Step Guide
Calculating the percentage increase is a fundamental skill used in finance, statistics, and daily life. Whether you are tracking a salary raise, a population boom, or a rise in product prices, understanding the relative growth of a value is essential for accurate data analysis.
The Percentage Increase Formula
To find the percentage increase between two numbers, you can use the following formula:
Percentage Increase = [(New Value – Original Value) / |Original Value|] × 100
Step-by-Step Instructions
Identify the Values: Determine your starting number (Original Value) and your ending number (New Value).
Find the Difference: Subtract the Original Value from the New Value.
Divide by Original: Take the result from the previous step and divide it by the Original Value.
Convert to Percentage: Multiply that result by 100 to get the final percentage.
Practical Examples
Example 1: Salary Increase
Imagine you earned $50,000 last year and your salary was raised to $55,000 this year.
Difference: 55,000 – 50,000 = 5,000
Division: 5,000 / 50,000 = 0.10
Percentage: 0.10 × 100 = 10% increase.
Example 2: Website Traffic
A website had 1,200 visitors in January and 1,800 visitors in February.
Difference: 1,800 – 1,200 = 600
Division: 600 / 1,200 = 0.50
Percentage: 0.50 × 100 = 50% increase.
Why It Matters
Using a percentage provides context that raw numbers cannot. An increase of 10 units might be massive if the original value was 5 (a 200% increase), but it is negligible if the original value was 1,000,000 (a 0.001% increase). Calculating the percentage allows for better comparison across different scales of data.