How to calculate exchange rate: a step-by-step business guide

Key  takeaways

• The global foreign exchange market is the most active financial ecosystem in the world, with average daily turnover reaching a record $9.6 trillion¹.   

• Accurate currency conversion relies on three essential formulas, multiplication for budgeting, division for invoices, and division of totals for auditing provider rates.   

• Modern fintech solutions allow businesses to bypass the 3% or higher markups often hidden by traditional banks by utilizing local payment rails in over 120 countries.   

For global enterprises, the discrepancy between a competitive and a disadvantageous exchange rate extends beyond minor accounting adjustments; it represents the difference between a profitable quarter and a significant deficit. Whether an organization is settling an international supplier invoice, managing global payroll, or calculating the impact of foreign exchange volatility on consolidated revenue, a nuanced understanding of the mathematical mechanics behind currency conversion is paramount. 

As cross-border trade becomes increasingly integrated into the operations of even the smallest startups, the ability to manage these conversions with precision has transformed from a back-office function into a core strategic competency.

What is an exchange rate?

An exchange rate represents the relative price of one currency expressed in terms of another. It is the fundamental unit of value in international trade, dictating how much domestic currency is required to acquire a specific amount of foreign capital. In every currency pair, the first currency is the base currency, while the second is the quote currency. The value of the pair indicates how much of the quote currency is needed to purchase a single unit of the base currency.

For example, a quotation of EUR/USD = 1.13 signifies that €1 (the base) is worth $1.13 (the quote). Understanding these rates is the first step for businesses asking: Do you have what it takes to scale globally? In professional environments, rates are carried to four or five decimal places to account for "pips" (percentage in point), where small fractions represent significant value in high-volume trades.

How does the exchange rate work?

The mechanics of the exchange rate are driven by the collective sentiment and requirements of millions of market participants, ranging from central banks and commercial institutions to multinational corporations and individual traders. Because currencies are traded globally across multiple time zones, the market remains operational 24 hours a day, beginning the trading week in Sydney and moving through Tokyo, London, and New York before closing on Friday evening.   

The price of a currency at any given moment reflects the market's assessment of that nation's economic health, political stability, and monetary policy relative to its peers. If a country experiences robust economic growth, it often attracts foreign direct investment. To participate in that economy, investors must purchase the local currency, thereby increasing demand. When demand exceeds the available supply on the open market, the currency's value appreciates. Conversely, if an economy faces a recession or high inflation, investors may sell their holdings to move capital into more stable environments, causing the currency's value to depreciate.

In the retail and business banking sectors, the rates provided to customers are derived from the interbank rate, the wholesale price at which large financial institutions trade massive volumes of currency. Banks and brokers add a 'spread' to this interbank rate, which is the difference between the 'buy' price and the 'sell' price. This spread covers the provider's operational costs and ensures a profit margin on each transaction. Consequently, the rate a business sees on a public search engine like Google is the interbank mid-market rate, while the rate they are offered by a traditional bank is almost always less favorable due to these added layers of cost.   

The currency conversion formula

Developing a rigorous process for currency calculation is a necessity for maintaining accurate financial ledgers and ensuring that international transactions remain within budget.

1. Converting local to foreign (multiplication)

This formula is utilized when an organization has a set amount of local currency and needs to determine the equivalent value in a foreign currency for budgeting, making a purchase, or calculating a foreign payout.   

The formula is as follows:

Starting Amount (Local)×Exchange Rate=Foreign Amount

For a US-based organization intending to send money to a supplier in the United Kingdom with a GBP/USD exchange rate of 1.25, the calculation for $100,000 would be:

$100,000×1.25=£125,000

This straightforward calculation allows the finance team to project the exact amount the recipient will receive in their local denomination.

2. Converting foreign to local (division)

This calculation is critical when an organization receives an invoice in a foreign currency and needs to determine the exact cost to their domestic business account.   

The formula is as follows:

Foreign Amount/Exchange Rate=Local Cost

If a US-based company receives an invoice for €50,000 and the EUR/USD exchange rate is 1.10, the cost in US Dollars would be:

€50,000/1.10=$45,454.55

Mastering this formula is essential for treasury management, as it prevents unexpected cash flow shortfalls when settling foreign debts.

3. Calculating the rate from a receipt

After a transaction has occurred, it is vital to audit the actual exchange rate applied by the financial provider. This step reveals the true cost of the transaction, including any hidden fees or markups that were built into the rate.   

The formula is as follows:

Foreign Currency Received/Local Currency Paid=The Applied Exchange Rate

For example, if a business paid $10,800 to receive £8,000, the applied rate was:

£8,000/$10,800=0.7407

Mastering these formulas is a key component of effective foreign exchange risk management.

6 factors influencing exchange rates

The volatility of exchange rates is rarely the result of a single event; rather, it is the product of a complex interplay of macroeconomic indicators, central bank policies, and global market sentiment. Understanding these factors allows finance leaders to better anticipate shifts and implement effective hedging strategies.

• Interest Rates: Controlled by central banks to manage growth. Higher rates attract foreign capital seeking better returns, leading to currency appreciation.

• Inflation Rates: The rate at which the cost of goods increases. Countries with consistently lower inflation see their currency value increase as purchasing power is maintained.

• Economic Indicators: Metrics such as GDP growth and employment levels. Strong performance boosts investor confidence and demand for the domestic currency.

• Political Stability: Perception of risk regarding elections or policy changes. Stable environments attract investment, while uncertainty typically leads to depreciation.   

• Trade Balance: The difference between exports and imports. A surplus increases demand for the local currency as foreign buyers must acquire it to pay for exports.

• Speculation: Traders buying or selling based on expectations. If investors believe a currency will strengthen, they buy it in bulk, creating a self-fulfilling price hike.

Track real-time currency exchange rate

While the factors above drive long-term trends, exchange rates change by the second. To see how these macroeconomic shifts are currently affecting your specific currency needs, use our live conversion tools. Popular Currency Conversions:

• GBP to USD – Track the British Pound against the US Dollar.

• USD to CAD – View the latest rates for the US Dollar to the Canadian Dollar.

• EUR to USD – Monitor the Euro to US Dollar.

• AUD to USD – Check the Australian Dollar’s exchange rate to the US Dollar.

Need a different exchange rate? We support over 100+ global currencies. Visit our All Currency Converter to select your specific currency pair and get an instant, up-to-the-minute rate.

How banks calculate your exchange rate: the truth about markups

The rate quoted on financial news sites is the interbank rate, the price at which banks trade with one another. However, for most businesses, this rate remains inaccessible. Retail banks typically calculate an "all-in" rate for their customers by adding hidden markups to the interbank price. This practice can result in a significant disconnect between the actual market value of the currency and the price a business pays.

The financial consequences of these markups are particularly evident in high-value transactions. Consider an organization making a $200,000 payment to an international vendor. A traditional bank applying a 3% hidden markup to the foreign exchange rate formula results in a cost of $6,000 for that single transfer.

SWIFT vs. local payment rails: choosing the right method

Selecting the appropriate international payment method for global fund transfers is as critical as securing a competitive exchange rate. The method used impacts the final cost, the speed of delivery, and the predictability of the transaction for both the sender and the recipient.

SWIFT Transfers

• Global reach: SWIFT remains the most comprehensive network, capable of reaching almost any bank globally.   

• Reliability for large settlements: The system is highly standardized and is the preferred method for very large-scale corporate settlements.   

• Intermediary fees: Because funds pass through "correspondent" banks, each institutional step may deduct an unpredictable fee.   

• Slower processing times: The multi-step nature of the network means transfers typically take three to five business days.   

Local Payment Rails

• Faster delivery: By bypassing the correspondent banking network, local rail transfers often arrive within a few hours or on the same day.   

• Lower costs: Eliminating intermediary banks removes associated hidden fees; many platforms provide local transfers for $0.   

• High predictability: Senders can be certain of the exact amount reaching the recipient because there are no surprise deductions.   

• Simplified reconciliation: Payments arrive via domestic methods, making them easier for accounting software to identify and reconcile.

Where are places that you can exchange currency?

For a global business, the choice of where to exchange currency depends on transaction volume, speed, and technical integration requirements.

• Traditional Banking Institutions: Banks are trusted but often the most expensive option due to high markups and opaque fee structures. They are suitable for infrequent, low-volume needs but can drain resources for high-growth global companies.   

• Specialist Foreign Exchange (FX) Providers: These providers focus exclusively on currency and offer more competitive rates than retail banks. While effective for large transactions, they may lack the integrated digital experience required by modern businesses.   

• Fintech Currency Platforms: Platforms like Airwallex combine competitive rates with advanced financial software for managing collections and payouts from one dashboard. They offer high transparency, real-time processing, and automation through APIs.

• Physical Currency Bureaus: Designed for travelers, physical bureaus, especially airport kiosks, should be avoided by businesses. They typically offer the least favorable rates in the market due to high overheads and a captive audience.   

Transact like a local with Airwallex Global Accounts

Opening and maintaining physical bank accounts in every country where an organization operates is a time-consuming and manual process. Airwallex Global Accounts provide a modern alternative, allowing businesses to launch in new markets quickly by providing dedicated local account details in over 20 currencies.   

These accounts function as domestic accounts in the target region, allowing an organization to:

• Collect funds locally: Provide customers with local bank codes to receive payments via domestic methods like ACH in the US or SEPA in Europe.   

• Avoid forced conversions: Collect payments in the customer's local currency and hold them in a multi-currency wallet to prevent "double conversion" costs.   

• Reduce transfer surcharges: By receiving funds via domestic rails, businesses bypass the high surcharges associated with international SWIFT transfers.   

• Centralized management: Manage balances and move to a continuous close by integrating with accounting software for real-time visibility.

Frequently asked questions about how to calculate exchange rates

Should I exchange money before I travel or when I arrive?

For business travel, it is most efficient to use multi-currency corporate cards that offer interbank rates rather than carrying bulk cash. If cash is necessary, exchanging money through a fintech platform before departure is generally more cost-effective than using airport kiosks upon arrival.   

What is the mid-market rate and why is it different from what the bank is showing me?

The mid-market rate is the real-time midpoint between the global buy and sell prices for a currency. Banks show a different rate because they add a hidden markup to the mid-market rate to ensure their own profit margin on the transaction.   

What is the difference between a 'spot' rate and a 'forward' rate?

A spot rate is the current market price for immediate exchange, typically settling within two business days. A forward rate is a predetermined exchange rate used to lock in a price today for a transaction that will occur on a specific future date.   

When is the best time to exchange money?

The market is most liquid during the overlap between the London and New York sessions, typically between 8:00 am and 12:00 pm EST. High trading volumes during this window often lead to narrower spreads and more stable pricing for business transactions.   

How can I lock in an exchange rate for a future payment?

Businesses can utilize Forward Exchange Contracts (FECs) to fix a rate today for payments occurring months in the future. Additionally, some platforms offer shorter-term "Quotes" that guarantee a specific rate for up to 24 hours.   

What are the fees for international wire transfers compared to online services like Airwallex and Wise?

Traditional banks often charge $35 to $50 for international wires, plus hidden currency markups that exceed 3%. In contrast, online services use local payment rails to offer transfers for significantly lower fees, often $0 for local transactions and transparent markups.   

Sources

1. https://www.bis.org/press/p250930.htm