Guide
How Exchange Rates Are Set
Some currencies float freely, some are pinned to another currency, and many sit in between. Knowing which regime a currency follows explains most of its behavior, from the euro's daily drift to the yuan's narrow range.
Floating currencies and market forces
The US dollar, euro, Japanese yen, British pound, Canadian dollar, Australian dollar, and most other major currencies float. Their exchange rates are set by the foreign exchange market, the largest financial market in the world, where banks, fund managers, corporations, governments, and individuals trade continuously. Volume is enormous, and prices adjust in real time to every piece of news.
In a floating system, no authority promises any particular level. If the market decides a currency is worth less, it falls. This sounds unstable, but floating acts as a shock absorber: when a country faces economic stress, its currency adjusts gradually rather than forcing an abrupt policy crisis. It also lets monetary policy focus on domestic goals such as inflation and employment.
The rate you see for a floating pair, such as the EUR/USD quote behind our converter, is therefore an emergent price, not a decision. It reflects the aggregated expectations of everyone trading at that moment.
The role of interest rates
Interest rates are the single most persistent driver of floating exchange rates. Currencies are like any asset: investors want the ones that offer better risk-adjusted returns. When a central bank raises rates, holding that currency becomes more attractive, and demand tends to push its value up. When rates fall, money often flows elsewhere.
This is why exchange rates move sharply around central bank meetings and inflation reports. A surprise interest rate decision can move a major pair by a full percentage point within hours, which is huge by currency standards. Traders watch the difference between two countries' rates, known as the rate differential, more than either level alone.
For everyday users the lesson is practical: rate announcements create volatility. If you have a large conversion coming, be aware of scheduled central bank meetings and inflation releases for both currencies involved. Planning around them is easier than predicting them.
Inflation, trade, and capital flows
Over longer horizons, inflation dominates. A country with persistently higher inflation sees its currency buy less over time, because its goods become relatively expensive and its money loses purchasing power. Currencies of low-inflation economies, such as the Swiss franc, tend to hold or gain value against higher-inflation peers across decades.
Trade balances matter too. A country selling more than it buys earns net inflows of foreign currency, supporting its own. Investment flows, including foreign purchases of stocks, bonds, and property, often dwarf trade flows. A currency can strengthen even with a trade deficit if global investors are pouring capital into its markets, as has often happened with the US dollar.
Finally, risk sentiment moves money in cycles. In calm periods, investors reach for higher yields, benefiting emerging market currencies. In stressed periods, they retreat to safe havens such as the dollar, the yen, and the franc. These swings can override fundamentals for weeks or months.
Fixed and pegged currencies
Some currencies do not float at all. Their government fixes the exchange rate against another currency, often the US dollar, and commits to defending that level. The Hong Kong dollar, for example, has been pegged to the US dollar in a narrow band since 1983, and the UAE dirham has been pegged to the dollar for decades. For these currencies, our converter's rate barely moves from day to day, and that is by design.
Maintaining a peg requires reserves and discipline. The central bank must stand ready to buy or sell its currency whenever the market pushes toward the edge of the band. If it runs out of reserves or credibility, the peg can break suddenly, as history has shown in repeated currency crises. Pegs work well for small open economies that want stability and trade heavily with the anchor country.
The practical consequence for you is simple: converting between a pegged currency and its anchor is nearly rate-free in direction, so the cost you pay is almost entirely the provider's margin. Shopping around matters even more when the market rate itself is fixed.
Managed floats: the middle ground
Between free floating and fixed pegs lies the managed float, where a currency mostly trades on markets but the central bank intervenes to smooth swings or lean against extremes. The Chinese yuan is the most prominent example. The People's Bank of China sets a daily reference point and allows trading within a limited band around it, while nudging the reference over time in line with economic strategy.
Managed floats try to combine market pricing with stability. Critics argue they can mask underlying pressure until it releases abruptly. Supporters argue they protect exporters and financial systems from destabilizing swings. Either way, understanding that a currency is managed changes your expectations: daily moves are smaller, but policy shifts can reprice the currency in steps.
If you convert USD to CNY regularly, our USD to CNY guide covers the onshore and offshore yuan, and why they sometimes differ.
What actually moves rates day to day
Day-to-day movement comes from a surprisingly short list: scheduled economic data such as inflation, employment, and growth figures; central bank decisions and speeches; political and geopolitical events; large trades by institutions; and shifts in risk appetite. Unscheduled surprises, like a bank failure or a sudden policy change, can cause the largest jumps.
For a person converting money, the practical takeaway is scale. Major floating pairs typically move less than one percent per day and a few percent per month. That is small compared with the spread difference between a good provider and a bad one, which can easily be two to five percent. This is why we recommend choosing the method first, and only then worrying about timing, as explained in our article on the best time to exchange currency.
If you are curious how quotes are constructed from these market prices, start with our exchange rate basics guide, or compare provider markups directly in the mid-market rate explained guide.