Historical Exchange Rate Calculator
This calculator allows you to find the exchange rate between two currencies on a specific past date. Exchange rates fluctuate constantly due to economic factors, political events, and market sentiment. By checking historical data, you can understand past currency values, analyze trends, and inform future financial decisions.
function calculateExchangeRate() {
var baseCurrency = document.getElementById("baseCurrency").value.toUpperCase();
var targetCurrency = document.getElementById("targetCurrency").value.toUpperCase();
var exchangeDate = document.getElementById("exchangeDate").value;
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (!baseCurrency || !targetCurrency || !exchangeDate) {
resultDiv.innerHTML = "Please fill in all fields.";
return;
}
// Placeholder for API call. In a real-world scenario, you would
// fetch historical exchange rate data from a reliable financial API
// (e.g., Open Exchange Rates, ExchangeRate-API, Fixer.io).
// The API would return data structured like:
// { "date": "2023-10-27", "rates": { "USD": { "EUR": 0.945 }, "EUR": { "USD": 1.058 } } }
// For this example, we'll simulate a result.
// Simulate fetching data – REPLACE with actual API call
simulateApiCall(baseCurrency, targetCurrency, exchangeDate)
.then(function(rateData) {
if (rateData && rateData.rate) {
var rate = rateData.rate;
var displayRate = rate.toFixed(6); // Display with reasonable precision
resultDiv.innerHTML =
"On " + exchangeDate + ", " +
"1 " + baseCurrency + " was equal to " +
displayRate + " " + targetCurrency + ".";
} else {
resultDiv.innerHTML = "Could not retrieve exchange rate for the specified date and currencies. Please ensure currencies are valid and try again.";
}
})
.catch(function(error) {
console.error("API Error:", error);
resultDiv.innerHTML = "An error occurred while fetching the exchange rate.";
});
}
// — Simulation Function (REPLACE with actual API integration) —
function simulateApiCall(base, target, date) {
return new Promise(function(resolve, reject) {
// Simulate network delay
setTimeout(function() {
// Basic validation and mock data generation
if (base === "USD" && target === "EUR" && date >= "2020-01-01") {
// Example: Rates fluctuate, let's make a simple progression
var dateObj = new Date(date);
var startYear = 2020;
var currentYear = dateObj.getFullYear();
var yearDiff = currentYear – startYear;
var mockRate = 0.88 + (yearDiff * 0.015) + Math.random() * 0.03; // Simple mock
resolve({ "date": date, "rates": { [base]: { [target]: mockRate } } });
} else if (base === "EUR" && target === "USD" && date >= "2020-01-01") {
var dateObj = new Date(date);
var startYear = 2020;
var currentYear = dateObj.getFullYear();
var yearDiff = currentYear – startYear;
var mockRate = 1.12 + (yearDiff * 0.01) + Math.random() * 0.02; // Simple mock
resolve({ "date": date, "rates": { [base]: { [target]: mockRate } } });
} else if (base === "GBP" && target === "JPY" && date >= "2020-01-01") {
var dateObj = new Date(date);
var startYear = 2020;
var currentYear = dateObj.getFullYear();
var yearDiff = currentYear – startYear;
var mockRate = 145.50 + (yearDiff * 10.50) + Math.random() * 15; // Simple mock
resolve({ "date": date, "rates": { [base]: { [target]: mockRate } } });
}
else {
// Simulate an error for unsupported currency pairs or dates
reject("Unsupported currency pair or date for simulation.");
}
}, 500); // 0.5 second delay
});
}
// — Helper to extract rate from simulated data —
// This would be part of your actual API response handling
function extractRateFromApiResponse(apiResponse, base, target) {
if (apiResponse && apiResponse.rates && apiResponse.rates[base] && apiResponse.rates[base][target]) {
return apiResponse.rates[base][target];
}
return null;
}
// Modify calculateExchangeRate to use the helper
function calculateExchangeRate() {
var baseCurrency = document.getElementById("baseCurrency").value.toUpperCase();
var targetCurrency = document.getElementById("targetCurrency").value.toUpperCase();
var exchangeDate = document.getElementById("exchangeDate").value;
var resultDiv = document.getElementById("result");
resultDiv.innerHTML = ""; // Clear previous results
if (!baseCurrency || !targetCurrency || !exchangeDate) {
resultDiv.innerHTML = "Please fill in all fields.";
return;
}
simulateApiCall(baseCurrency, targetCurrency, exchangeDate)
.then(function(rateData) {
var rate = extractRateFromApiResponse(rateData, baseCurrency, targetCurrency);
if (rate !== null) {
var displayRate = rate.toFixed(6); // Display with reasonable precision
resultDiv.innerHTML =
"On " + exchangeDate + ", " +
"1 " + baseCurrency + " was equal to " +
displayRate + " " + targetCurrency + ".";
} else {
resultDiv.innerHTML = "Could not retrieve exchange rate for the specified date and currencies. Please ensure currencies are valid and try again.";
}
})
.catch(function(error) {
console.error("API Error:", error);
resultDiv.innerHTML = "An error occurred while fetching the exchange rate.";
});
}
.calculator-container {
font-family: sans-serif;
border: 1px solid #ccc;
padding: 20px;
border-radius: 8px;
max-width: 500px;
margin: 20px auto;
background-color: #f9f9f9;
}
.calculator-container h2 {
text-align: center;
margin-bottom: 15px;
color: #333;
}
.calculator-container p {
color: #555;
line-height: 1.6;
margin-bottom: 20px;
}
.input-section {
display: grid;
grid-template-columns: 1fr;
gap: 15px;
}
.form-group {
display: flex;
flex-direction: column;
}
.form-group label {
margin-bottom: 5px;
font-weight: bold;
color: #444;
}
.form-group input[type="text"],
.form-group input[type="date"] {
padding: 10px;
border: 1px solid #ccc;
border-radius: 4px;
font-size: 1rem;
width: 100%; /* Ensure input takes full width of its container */
box-sizing: border-box; /* Include padding and border in the element's total width and height */
}
button {
padding: 12px 20px;
background-color: #007bff;
color: white;
border: none;
border-radius: 4px;
cursor: pointer;
font-size: 1rem;
transition: background-color 0.3s ease;
width: 100%; /* Ensure button takes full width */
}
button:hover {
background-color: #0056b3;
}
#result {
margin-top: 25px;
padding: 15px;
background-color: #e9ecef;
border: 1px solid #ced4da;
border-radius: 4px;
text-align: center;
color: #333;
}
.error {
color: #dc3545;
font-weight: bold;
}