Calculate conversions using standard demo rates or enter a custom bank rate.
USD – US Dollar
EUR – Euro
GBP – British Pound
JPY – Japanese Yen
CAD – Canadian Dollar
AUD – Australian Dollar
CHF – Swiss Franc
CNY – Chinese Yuan
INR – Indian Rupee
EUR – Euro
USD – US Dollar
GBP – British Pound
JPY – Japanese Yen
CAD – Canadian Dollar
AUD – Australian Dollar
CHF – Swiss Franc
CNY – Chinese Yuan
INR – Indian Rupee
Leave blank to use standard market estimation.
Converted Amount
0.00
Exchange Rate Used
Inverse Rate
Original Amount
* Note: Standard rates are approximations for demonstration. Use "Custom Exchange Rate" for precise bank quotes.
function calculateExchange() {
// Inputs
var amountInput = document.getElementById('amount');
var fromSelect = document.getElementById('fromCurrency');
var toSelect = document.getElementById('toCurrency');
var customRateInput = document.getElementById('customRate');
var resultBox = document.getElementById('resultBox');
var amount = parseFloat(amountInput.value);
var fromCurr = fromSelect.value;
var toCurr = toSelect.value;
var customRate = parseFloat(customRateInput.value);
// Validation
if (isNaN(amount) || amount 0) {
// Use custom manual rate if provided
exchangeRate = customRate;
} else {
// Calculate cross rate via USD
// Formula: (TargetRate / SourceRate)
var sourceRateToUSD = rates[fromCurr];
var targetRateToUSD = rates[toCurr];
exchangeRate = targetRateToUSD / sourceRateToUSD;
}
var convertedAmount = amount * exchangeRate;
var inverse = 1 / exchangeRate;
// Formatting
var locale = "en-US";
var currencyFormatter = new Intl.NumberFormat(locale, {
style: 'currency',
currency: toCurr,
minimumFractionDigits: 2,
maximumFractionDigits: 2
});
var sourceFormatter = new Intl.NumberFormat(locale, {
style: 'currency',
currency: fromCurr,
minimumFractionDigits: 2,
maximumFractionDigits: 2
});
// Display Results
document.getElementById('finalAmount').innerHTML = currencyFormatter.format(convertedAmount);
document.getElementById('currencyLabel').innerHTML = toCurr;
// Rate display: 1 FROM = X TO
document.getElementById('rateUsed').innerHTML = "1 " + fromCurr + " = " + exchangeRate.toFixed(4) + " " + toCurr;
// Inverse display: 1 TO = X FROM
document.getElementById('inverseRate').innerHTML = "1 " + toCurr + " = " + inverse.toFixed(4) + " " + fromCurr;
document.getElementById('originalAmountDisplay').innerHTML = sourceFormatter.format(amount);
resultBox.style.display = 'block';
}
Understanding Exchange Rate Calculations
Foreign exchange (Forex) is the backbone of international trade and travel. Whether you are a business paying an overseas supplier or a tourist planning a vacation, understanding how exchange rates work is crucial for financial planning. This calculator helps you determine the value of one currency relative to another, either using standard market estimations or a specific rate provided by your financial institution.
How Exchange Rates are Determined
Exchange rates typically float freely against one another, meaning they are in constant fluctuation. The value is determined by the supply and demand for each currency in the global market. Key factors influencing these rates include:
Interest Rates: Central banks influence currency value by adjusting interest rates. Higher rates generally offer better returns to lenders, attracting foreign capital and raising the currency's value.
Inflation: Typically, a country with a consistently lower inflation rate exhibits a rising currency value, as its purchasing power increases relative to other currencies.
Economic Performance: Strong economic data, such as GDP growth and employment figures, tends to strengthen a currency.
Political Stability: Investors prefer stable countries with strong economic performance. Turmoil can cause a currency to depreciate.
The Math Behind Currency Conversion
While online tools make it easy, understanding the math is helpful for quick mental estimates. The formula for converting currency is straightforward:
Total Target Currency = Amount of Source Currency × Exchange Rate
For example, if you have 1,000 US Dollars (USD) and want to convert them to Euros (EUR), and the exchange rate is 0.92 (meaning 1 USD = 0.92 EUR), the calculation is:
1,000 × 0.92 = 920 EUR
Bid vs. Ask: The Hidden Costs
When you exchange money at a bank or airport kiosk, you will rarely get the "mid-market" rate (the rate shown on Google or news sites). Financial institutions make money on the spread:
Buy Rate (Bid): The price at which the dealer will buy the foreign currency from you.
Sell Rate (Ask): The price at which the dealer will sell the foreign currency to you.
The Spread is the difference between these two. If the mid-market rate is 1.00, a bank might sell to you at 1.03 and buy from you at 0.97. The "Custom Exchange Rate" field in our calculator allows you to input the actual rate offered by your bank to see exactly how much money you will receive after these hidden costs.
Cross Rates
A cross rate is an exchange rate between two currencies that does not involve the US Dollar. While most currencies are traded against the USD, cross rates (like EUR/GBP) are calculated mathematically by comparing the value of both currencies against the USD. Our calculator handles this automatically by determining the relative value of the source and target currencies based on a common baseline.
Using This Calculator for Budgeting
To use this tool effectively for travel or business budgeting:
Check the Spot Rate: Look up the current mid-market rate for a baseline.
Get a Quote: Check your bank or credit card's foreign transaction fee or exchange rate.
Input Custom Rate: Enter the bank's rate into the "Custom Rate" field to see the real-world conversion, which often differs from the theoretical market rate.