Exchange rates can feel arbitrary, but they follow clear forces. For the world’s major currencies, no one “sets” the rate in the way a shop sets a price. Instead it emerges, second by second, from a vast global market — shaped by interest rates, inflation, trade, and central-bank policy.
Who decides what a currency is worth?
For freely-traded currencies such as the US dollar, euro, and British pound, the rate is set by the foreign-exchange (forex) market — the largest financial market in the world. According to the Bank for International Settlements’ triennial survey, global FX trading turnover is measured in trillions of US dollars per day.
Banks, hedge funds, corporations and governments constantly buy and sell currencies. The price at which they trade is the mid-market rate — the midpoint between the highest buy offer and the lowest sell offer at any moment. That is the same neutral benchmark behind our live currency converter and every currency pair page.
What drives currency supply and demand?
A handful of fundamental forces push exchange rates up and down:
- Interest rates. Higher rates attract foreign capital seeking returns, increasing demand for the currency and pushing it up.
- Inflation. Lower, stable inflation tends to support a currency’s value over time; high inflation erodes it.
- Trade balances. A country exporting more than it imports sees demand for its currency rise as buyers pay for those exports.
- Investor sentiment and risk. In turbulent times, money flows to “safe-haven” currencies, raising their value regardless of fundamentals.
- Political and economic stability. Predictable policy and strong institutions attract investment and support the currency.
Floating vs fixed: how rates are determined
Not every country lets its currency float. There are three broad regimes:
| Regime | How the rate is set | Example characteristics |
|---|---|---|
| Floating | Pure market supply and demand | Moves continuously; no target value |
| Managed float | Mostly market, with occasional central-bank intervention | Smoothed volatility, soft guidance |
| Fixed / pegged | Government or central bank holds a set value | Maintained using foreign-currency reserves |
Major reserve currencies — USD, EUR, GBP, JPY — float. Several Gulf currencies, by contrast, are pegged to the US dollar, which is why the UAE Dirham to Indian Rupee rate tends to move only because of the rupee side, not the dirham. Understanding the regime tells you why some pairs are stable and others swing.
How do central banks influence the rate?
Central banks such as the European Central Bank and the US Federal Reserve do not usually dictate exchange rates directly for floating currencies. They influence them through:
- Monetary policy — setting benchmark interest rates, which changes the return on holding the currency.
- Open-market operations and quantitative easing — changing how much currency is in circulation.
- Foreign-exchange intervention — occasionally buying or selling currency to smooth extreme moves.
- Reference rates — publishing daily benchmark rates, like the ECB reference rates that anchor much of Europe’s pricing.
For a pegged currency, the central bank’s role is far more active: it must stand ready to buy or sell unlimited amounts to defend the peg.
Why your rate still differs from “the” exchange rate
Even though the market sets one mid-market rate, you never transact at it as a retail customer. Banks and transfer services add a margin on top — the difference between the wholesale rate and your retail rate. That gap, not the market itself, is what determines how much you actually pay. See mid-market rate vs the rate your bank gives you for exactly how that works, and currency spreads and hidden transfer fees explained for where the margin goes.
The bottom line
For major currencies, the exchange rate is a live, market-set price reflecting interest rates, inflation, trade and sentiment — not a figure decreed by any single authority. Central banks steer it; markets set it; and the rate you personally receive is that market rate minus the provider’s margin. Knowing which forces are moving a currency helps you read the headlines, and knowing about the margin helps you keep more of your money.
General information only, not financial advice.