Pecentage Calculator

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Percentage Calculator body { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f8f9fa; color: #333; line-height: 1.6; margin: 0; padding: 0; display: flex; justify-content: center; align-items: flex-start; min-height: 100vh; } .loan-calc-container { background-color: #ffffff; border-radius: 8px; box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1); margin: 20px; padding: 30px; width: 100%; max-width: 700px; box-sizing: border-box; } h1, h2 { color: #004a99; text-align: center; margin-bottom: 20px; } .input-group { margin-bottom: 15px; display: flex; flex-direction: column; } .input-group label { font-weight: bold; margin-bottom: 8px; color: #004a99; } .input-group input[type="number"] { padding: 10px; border: 1px solid #ccc; border-radius: 4px; font-size: 1rem; box-sizing: border-box; width: 100%; } .button-group { text-align: center; margin-top: 25px; margin-bottom: 30px; } button { background-color: #004a99; color: white; border: none; padding: 12px 25px; border-radius: 4px; font-size: 1.1rem; cursor: pointer; transition: background-color 0.3s ease; } button:hover { background-color: #003b7a; } #result { background-color: #e6f2ff; padding: 20px; border-radius: 4px; border: 1px dashed #004a99; text-align: center; margin-top: 20px; font-size: 1.5rem; font-weight: bold; color: #004a99; } #result span { color: #28a745; } .article-section { margin-top: 40px; padding-top: 30px; border-top: 1px solid #eee; } .article-section h2 { margin-bottom: 15px; } .article-section p, .article-section ul { margin-bottom: 15px; } .article-section ul { padding-left: 20px; } .article-section li { margin-bottom: 8px; } @media (max-width: 600px) { .loan-calc-container { padding: 20px; } button { width: 100%; padding: 15px; } #result { font-size: 1.2rem; } }

Percentage Calculator

Understanding Percentages

A percentage is a number or ratio expressed as a fraction of 100. The word "percent" comes from the Latin phrase "per centum," meaning "by the hundred." It's a powerful tool used in finance, statistics, everyday shopping, and many other fields to express proportions and changes in a standardized way.

Common Percentage Calculations

The percentage calculator above can help with three fundamental types of percentage calculations:

1. Calculating a Percentage of a Number

This answers the question: "What is X% of Y?". For example, "What is 15% of $200?".

Formula: (Percentage / 100) * Original Value

Example: To find 15% of $200, you calculate (15 / 100) * 200 = 0.15 * 200 = $30.

2. Calculating What Percentage One Number Is of Another

This answers the question: "What percentage is X of Y?". For example, "What percentage is $30 of $200?".

Formula: (Part / Whole) * 100

Example: To find what percentage $30 is of $200, you calculate (30 / 200) * 100 = 0.15 * 100 = 15%.

3. Calculating Percentage Increase or Decrease

This answers the question: "What is the percentage change from X to Y?". For example, "What is the percentage increase from $200 to $230?".

Formula: ((New Value – Original Value) / Original Value) * 100

Example: To find the percentage increase from $200 to $230:

  • Difference: $230 – $200 = $30
  • Change as a fraction of original: $30 / $200 = 0.15
  • Percentage change: 0.15 * 100 = 15% increase.

For a decrease, the result will be negative. For example, a decrease from $230 to $200 would be (($200 – $230) / $230) * 100 = (-$30 / $230) * 100 ≈ -13.04%.

Uses of Percentage Calculators

  • Finance: Calculating interest, discounts, taxes, returns on investment, and growth rates.
  • Shopping: Determining savings from sales and discounts.
  • Statistics: Understanding proportions in data sets, survey results, and election outcomes.
  • Everyday Life: Adjusting recipes, calculating tips, and understanding various reports.
function calculatePercentage() { var valueInput = document.getElementById("value"); var percentageInput = document.getElementById("percentage"); var resultDiv = document.getElementById("result"); var value = parseFloat(valueInput.value); var percentage = parseFloat(percentageInput.value); if (isNaN(value) || isNaN(percentage)) { resultDiv.innerHTML = "Please enter valid numbers for both fields."; return; } var result = (percentage / 100) * value; if (isNaN(result)) { resultDiv.innerHTML = "Calculation error. Please check inputs."; } else { resultDiv.innerHTML = "" + result.toFixed(2) + ""; } } function calculatePercentageOfWhat() { var valueInput = document.getElementById("value"); // This is now the 'part' var percentageInput = document.getElementById("percentage"); // This is now the 'whole' var resultDiv = document.getElementById("result"); var part = parseFloat(valueInput.value); var whole = parseFloat(percentageInput.value); if (isNaN(part) || isNaN(whole)) { resultDiv.innerHTML = "Please enter valid numbers for both fields."; return; } if (whole === 0) { resultDiv.innerHTML = "The 'whole' value cannot be zero."; return; } var result = (part / whole) * 100; if (isNaN(result)) { resultDiv.innerHTML = "Calculation error. Please check inputs."; } else { resultDiv.innerHTML = "" + result.toFixed(2) + "%"; } } function calculateIncreaseOrDecrease() { var valueInput = document.getElementById("value"); // This is now the 'original value' var percentageInput = document.getElementById("percentage"); // This is now the 'new value' var resultDiv = document.getElementById("result"); var originalValue = parseFloat(valueInput.value); var newValue = parseFloat(percentageInput.value); if (isNaN(originalValue) || isNaN(newValue)) { resultDiv.innerHTML = "Please enter valid numbers for both fields."; return; } if (originalValue === 0) { resultDiv.innerHTML = "The 'original value' cannot be zero for percentage change calculation."; return; } var difference = newValue – originalValue; var result = (difference / originalValue) * 100; if (isNaN(result)) { resultDiv.innerHTML = "Calculation error. Please check inputs."; } else { var changeType = result >= 0 ? "increase" : "decrease"; resultDiv.innerHTML = "" + Math.abs(result).toFixed(2) + "% " + changeType; } }

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