.er-calculator-container {
max-width: 700px;
margin: 20px auto;
padding: 25px;
background-color: #f9f9f9;
border: 1px solid #e0e0e0;
border-radius: 8px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
.er-calculator-title {
text-align: center;
color: #2c3e50;
margin-bottom: 20px;
font-size: 24px;
}
.er-input-group {
margin-bottom: 15px;
}
.er-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #34495e;
}
.er-input-group input {
width: 100%;
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.er-btn {
width: 100%;
padding: 12px;
background-color: #2980b9;
color: white;
border: none;
border-radius: 4px;
font-size: 16px;
cursor: pointer;
transition: background-color 0.3s;
font-weight: bold;
}
.er-btn:hover {
background-color: #1f6391;
}
.er-result-box {
margin-top: 25px;
padding: 20px;
background-color: #fff;
border: 1px solid #ddd;
border-radius: 4px;
display: none;
}
.er-result-row {
display: flex;
justify-content: space-between;
margin-bottom: 10px;
padding-bottom: 10px;
border-bottom: 1px solid #eee;
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.er-result-row:last-child {
border-bottom: none;
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.er-label {
color: #7f8c8d;
font-weight: 500;
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.er-value {
font-weight: 700;
color: #2c3e50;
}
.er-positive {
color: #27ae60;
}
.er-negative {
color: #c0392b;
}
.er-content-section {
max-width: 800px;
margin: 40px auto;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
line-height: 1.6;
color: #333;
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.er-content-section h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 2px solid #3498db;
padding-bottom: 10px;
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.er-content-section h3 {
color: #34495e;
margin-top: 20px;
}
.er-content-section p {
margin-bottom: 15px;
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.er-content-section ul {
margin-bottom: 15px;
padding-left: 20px;
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.er-content-section li {
margin-bottom: 8px;
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.er-formula-box {
background-color: #ecf0f1;
padding: 15px;
border-left: 5px solid #2980b9;
font-family: "Courier New", Courier, monospace;
margin: 20px 0;
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function calculateFxChange() {
var oldRateInput = document.getElementById('oldRate');
var newRateInput = document.getElementById('newRate');
var resultBox = document.getElementById('resultBox');
var percentResult = document.getElementById('percentResult');
var diffResult = document.getElementById('diffResult');
var directionResult = document.getElementById('directionResult');
var oldRate = parseFloat(oldRateInput.value);
var newRate = parseFloat(newRateInput.value);
if (isNaN(oldRate) || isNaN(newRate)) {
alert("Please enter valid numbers for both exchange rates.");
return;
}
if (oldRate === 0) {
alert("The original exchange rate cannot be zero.");
return;
}
// Calculate Difference
var difference = newRate – oldRate;
// Calculate Percentage ((New – Old) / Old) * 100
var percentage = (difference / oldRate) * 100;
// Formatting
// Exchange rates often have 4 or 5 decimal places.
// We will display the difference to 5 decimals and percent to 2.
var formattedPercent = percentage.toFixed(2) + "%";
var formattedDiff = difference.toFixed(5);
// Update DOM
percentResult.innerHTML = formattedPercent;
diffResult.innerHTML = formattedDiff;
// Determine styling and text based on direction
if (percentage > 0) {
percentResult.className = "er-value er-positive";
diffResult.className = "er-value er-positive";
directionResult.innerHTML = "Appreciation (Base Currency Stronger)";
directionResult.className = "er-value er-positive";
} else if (percentage < 0) {
percentResult.className = "er-value er-negative";
diffResult.className = "er-value er-negative";
directionResult.innerHTML = "Depreciation (Base Currency Weaker)";
directionResult.className = "er-value er-negative";
} else {
percentResult.className = "er-value";
diffResult.className = "er-value";
directionResult.innerHTML = "No Change";
directionResult.className = "er-value";
}
resultBox.style.display = "block";
}
How to Calculate Percentage Change in Exchange Rate
Understanding currency fluctuations is essential for Forex traders, international businesses, and travelers. The exchange rate determines how much of one currency you can buy with another. When this rate moves, it represents either a strengthening (appreciation) or weakening (depreciation) of the base currency against the quote currency.
This guide explains the mathematics behind calculating the percentage change in exchange rates and how to interpret the data for financial analysis.
The Exchange Rate Percentage Formula
To calculate the percentage change between two exchange rates, you compare the difference between the new rate and the old rate relative to the original value. The formula is identical to calculating any standard percentage increase or decrease.
Percentage Change = ((New Rate – Old Rate) / Old Rate) × 100
Where:
- New Rate: The current market price or closing price of the currency pair.
- Old Rate: The entry price, opening price, or historical reference price.
Step-by-Step Calculation Example
Let's look at a practical example using the EUR/USD currency pair.
Scenario:
Imagine the EUR/USD exchange rate was 1.1000 yesterday (Old Rate). Today, the rate has moved to 1.1250 (New Rate).
1. Find the Difference
First, subtract the old rate from the new rate to find the absolute change.
1.1250 – 1.1000 = 0.0250
2. Divide by the Old Rate
Divide the difference by the original rate.
0.0250 / 1.1000 = 0.022727…
3. Convert to Percentage
Multiply the result by 100 to get the percentage.
0.022727 × 100 = 2.27%
Result: The Euro has appreciated by 2.27% against the US Dollar.
Interpreting the Results
When calculating exchange rate changes, the sign of the result (positive or negative) tells you the direction of the market.
- Positive (+) Percentage: The Base Currency (the first currency in the pair, e.g., EUR in EUR/USD) has increased in value. It now buys more of the quote currency. This is called Appreciation.
- Negative (-) Percentage: The Base Currency has decreased in value. It now buys less of the quote currency. This is called Depreciation.
Why Calculate Exchange Rate Changes?
Tracking percentage changes is more useful than tracking absolute price movements because it standardizes volatility across different pairs.
- For Travelers: Helps estimate how much more expensive or cheaper a trip has become compared to when you first budgeted for it.
- For Importers/Exporters: A small percentage change in rates can wipe out profit margins on large invoices.
- For Investors: FX changes impact the return on international investments. If you hold US stocks but your home currency strengthens by 5% against the dollar, your realized returns may be lower when converting back.
Common Terminology
Pips: In Forex, the "Percentage in Point" or Pip usually refers to the 4th decimal place (0.0001). While our calculator shows the total difference, traders often speak in pips (e.g., a move from 1.1000 to 1.1050 is a 50-pip move).
Base vs. Quote: In a pair like GBP/JPY, GBP is the base and JPY is the quote. The exchange rate represents how much JPY is needed to buy 1 GBP.