Why Do Currency Exchange Rates Change Every Day?

If you have ever converted money for travel, shopping online or sending funds abroad, you have probably noticed that the rate is rarely exactly the same two days in a row. Exchange rates move because currencies are traded continuously by banks, companies, investors and governments around the world. This article explains in plain language what moves them, why some currencies barely move at all, and why the rate you are offered can differ from the rate you see online. It is educational content, not advice to buy, sell or exchange any currency.

What is an exchange rate?

An exchange rate is the price of one currency in terms of another. If the euro-dollar rate is 1.10, one euro costs 1.10 US dollars. Because this is a price, it changes whenever the balance between buyers and sellers changes, in the same way the price of any traded asset can change. Rates are usually quoted as a pair, and the order matters: the same relationship can be written as 1 euro = 1.10 dollars, or 1 dollar = about 0.91 euros. The illustration below uses made-up round numbers to show the arithmetic.

Why the market never really sleeps

Foreign exchange is one of the largest financial markets in the world. According to the Bank for International Settlements, trading in over-the-counter foreign exchange markets averaged about 9.6 trillion US dollars per day in April 2025, and the US dollar was on one side of roughly 89% of all trades. Trading follows the sun across financial centres, with the United Kingdom accounting for the largest share of turnover. Because so many participants are trading at almost any hour on weekdays, new information can be reflected in prices within seconds.

The main things that move exchange rates

No single factor explains every move, and several of them often act at the same time. The table summarises the most commonly discussed drivers.

Floating, pegged and managed currencies

Not every currency moves freely. Many major currencies, including the US dollar, euro, British pound and Japanese yen, are generally described as floating: their value is set mainly by market trading, a system most large economies moved toward in the early 1970s. Other currencies are pegged or tightly managed. The Saudi riyal and the UAE dirham, for example, are linked to the US dollar at fixed official rates, which is why they barely move against it. Hong Kong operates a linked exchange rate system within a narrow band. In some countries, central banks or governments restrict how freely a currency can be traded, and the official rate and the rate people can actually get may differ. When you use a currency converter, it is worth knowing which kind of currency you are looking at.

Why the rate you get is not the rate you see

The rate shown on a search engine or a converter is usually a mid-market rate, a reference point halfway between what buyers and sellers are quoting. Banks, card networks, money transfer services and currency counters normally add a margin to that rate, charge a separate fee, or both. That is how many providers earn money, and it is why two services can quote noticeably different amounts on the same day. Weekends and holidays can also matter, because some rates are not updated while certain markets are closed.

The Sulivex calculator uses a public live exchange-rate feed to convert prices into the currency you choose. These figures are indicative and meant for comparison and learning. They are not the rate any bank or transfer service will necessarily offer you. If the live feed cannot be reached, the page falls back to stored approximate values and shows a note saying that live data is unavailable, so please check the note before relying on a number.

Why currencies matter for gold and other assets

Gold is priced mainly in US dollars on global markets, and many other assets are as well. That means a change in the dollar against your own currency can change what an asset costs in your local money, even when its dollar price has not moved. A stronger dollar can make dollar-priced assets more expensive for buyers who hold other currencies, and a weaker dollar can do the opposite, although many other forces affect demand at the same time. If you want to see how this works in practice, our article on what the gold spot price is and why it changes daily explains the pricing side, and Gold vs. Cryptocurrency compares gold with a different kind of asset. You can also try the currency selector in the Sulivex calculator to compare gold values in more than 100 currencies.

Common misunderstandings

• "A rising currency is always good." A stronger currency can make imports cheaper but can also make a country's exports more expensive for foreign buyers. Whether it is helpful depends on who you are and what you are doing.
• "Rates are set once a day." Some official reference rates are published daily, but market rates change continuously on weekdays.
• "The converter rate is what I will receive." Margins and fees usually apply, so the amount you receive is normally lower than the pure mid-market conversion.
• "Pegged means risk-free." A peg is a policy that a central bank maintains. Policies can change, and pegs have been adjusted or abandoned in the past.

Questions to ask before you exchange money

1. What is the mid-market rate right now, and how far is the rate I am being offered from it?
2. Is there a separate fee, and is it shown before I confirm?
3. Is the currency floating, pegged or restricted, and could that affect the rate I can actually get?
4. When will the money arrive, and could the rate change before the transaction is completed?
5. Am I comparing the total amount the recipient will receive, not just the headline rate?

Frequently asked questions

What is an exchange rate? An exchange rate is the price of one currency in terms of another. For example, the article's illustrative example uses 1 euro = 1.10 US dollars, so 100 euros would equal 110.00 US dollars at that illustrative rate. The illustration uses made-up round numbers and is not a current market quote.

What moves exchange rates? No single factor explains every move, and several often act at the same time: interest rates and central bank policy, inflation, economic data and growth, trade and capital flows, risk sentiment, commodity prices, politics and policy, and market expectations.

What is the difference between floating and pegged currencies? Many major currencies, including the US dollar, euro, British pound and Japanese yen, are generally described as floating, with their value set mainly by market trading. Other currencies are pegged or tightly managed: the Saudi riyal and the UAE dirham are linked to the US dollar at fixed official rates, and Hong Kong operates a linked exchange rate system within a narrow band.

Bottom line

Exchange rates change every day because currencies are prices, and prices respond to interest rates, inflation, trade, politics and expectations, all traded by participants in many time zones. Some currencies float freely, some are pegged, and the rate you actually receive is usually different from the one shown on a converter. Understanding those three points makes it easier to read currency numbers sensibly and to compare what different providers are really offering.