This guide explains how exchange rates work, why the rate you receive differs from the mid-market rate, and how travelers can minimize currency exchange costs.
An exchange rate is the price of one currency expressed in another. When USD/JPY = 149.50, one US dollar buys 149.50 Japanese yen. Rates fluctuate continuously based on international trade flows, investment activity, central bank decisions, inflation, and market sentiment.
Currencies are always quoted in pairs. GBP/USD = 1.27 means one British pound (base currency) buys $1.27 US dollars (quote currency). EZ Currency Calculator converts between any supported currencies using USD as a common intermediate, at mid-market rates.
The mid-market rate is the fair midpoint between buy and sell prices — the rate shown on EZ Currency Calculator and Google. When you exchange money, providers add a spread (their profit margin). Airport exchange desks: spread of 8–15%. Bank branches: 2–5%. Local ATMs: 1–3%. Good travel cards (Wise, Revolut, equivalent): 0.3–1%. On a $2,000 exchange, a 10% spread costs $200 more than a 1% spread.
Standard bank cards charge 1–3% on all foreign purchases. On a $3,000 holiday at 3%, that is $90 in fees. Many travel-focused cards waive this entirely. ATM withdrawal fees range from $2–$5 flat per transaction from your bank, plus potentially a fee from the ATM operator.
When a card machine abroad offers to charge you in your home currency instead of local currency, always decline. This is Dynamic Currency Conversion (DCC). The merchant's bank applies a poor exchange rate (3–8% worse than mid-market) and pockets the difference. Always pay in the local currency.
Exchange rates show how many currency units you get. Purchasing power parity (PPP) shows what those units actually buy. $100 in Vietnam covers many more days of food and accommodation than $100 in Switzerland, because local prices are fundamentally lower. EZ Currency Calculator's "what this buys" feature makes this difference concrete and immediately useful.
Central bank interest rate decisions, inflation rates, economic growth data, political stability, and market sentiment all affect exchange rates. Currencies of countries with higher inflation tend to weaken over time relative to lower-inflation countries.