An exchange rate is the value of one currency expressed in another currency, determined by supply and demand in the global foreign exchange market. If 1 USD equals 1.34 CAD today, that number is the exchange rate between the US dollar and the Canadian dollar, and it means 100 US dollars will buy you 134 Canadian dollars at that rate. The rate is not set by any single government or institution. It emerges continuously from millions of trades happening every second across banks, brokers, and electronic platforms around the world.
Understanding exchange rates matters whenever you travel abroad, send money to family in another country, shop on a foreign website, or receive payment in a currency that is not your own. The rate you see quoted and the rate you actually receive are often different, and that gap costs real money. This guide explains how rates are formed, what makes them move, and how to read a currency quote so you always know what you are getting.
Base currency and quote currency
Every exchange rate is written as a pair. The first currency in the pair is called the base currency and always equals exactly 1. The second currency is called the quote currency and tells you how much of it you need to buy one unit of the base.
| Pair | Base currency | Quote currency | What it means |
|---|---|---|---|
| USD/CAD = 1.34 | USD | CAD | 1 US dollar buys 1.34 Canadian dollars |
| EUR/USD = 1.08 | EUR | USD | 1 euro buys 1.08 US dollars |
| GBP/USD = 1.27 | GBP | USD | 1 British pound buys 1.27 US dollars |
| USD/JPY = 155 | USD | JPY | 1 US dollar buys 155 Japanese yen |
When people say the dollar is "strong," they mean the quote currency number is large, so each dollar buys a lot of foreign currency. When the dollar is "weak," the quote currency number is smaller. If you flip the pair around, you get the reciprocal: if 1 USD = 1.34 CAD, then 1 CAD = 1 / 1.34, which is about 0.746 USD.
A worked example: 100 USD to CAD
Suppose the USD/CAD exchange rate is 1.34. To find out how many Canadian dollars 100 US dollars will buy, multiply the amount by the rate:
- 100 USD multiplied by 1.34 = 134 CAD
- So 100 US dollars buys exactly 134 Canadian dollars at that rate.
- If the rate rises to 1.38, the same 100 USD now buys 138 CAD, meaning the US dollar has strengthened against the Canadian dollar.
- If the rate falls to 1.30, 100 USD only buys 130 CAD, meaning the US dollar has weakened.
The math is always the same: amount in base currency multiplied by the exchange rate equals the amount in the quote currency. The converter below does this calculation live for any pair.
The foreign exchange market
The foreign exchange market, almost always called the forex market or FX market, is the largest financial market in the world. It handles roughly 7.5 trillion US dollars in trading every single day, which dwarfs the combined volume of all the world's stock markets. Unlike stock exchanges, the forex market has no central location. It operates as a global network of banks, central banks, currency brokers, corporations, governments, and individual traders, connected electronically and open around the clock from Sunday evening to Friday evening US Eastern time.
The main participants in the forex market include:
- Commercial banks and investment banks: they trade currencies on behalf of clients and on their own account, and they form the interbank market where the purest mid-market rates are struck.
- Central banks: institutions like the US Federal Reserve, the European Central Bank, and the Bank of Japan can intervene to buy or sell their own currency to influence its level.
- Corporations: a company that sells products in Europe and gets paid in euros needs to convert those euros back to its home currency, creating steady real-economy demand.
- Retail brokers and money transfer services: platforms that let individuals and small businesses exchange currency, adding a markup to the interbank rate to earn their margin.
- Speculators and hedge funds: traders who bet on rate movements, adding significant volume and liquidity to the market.
Floating versus fixed exchange rates
Governments and central banks choose how much control they want over their currency. The two main systems are floating and fixed (pegged) rates.
A floating exchange rate moves freely in response to market forces. No government sets a target level, and the rate can rise or fall as much as supply and demand dictate. The US dollar, euro, British pound, Japanese yen, Australian dollar, and Canadian dollar all float. Most large developed economies use floating rates because they allow the currency to absorb economic shocks automatically. When a country runs a trade deficit, its currency tends to fall, which makes its exports cheaper and gradually corrects the imbalance without requiring government action.
A fixed or pegged exchange rate is tied to another currency at a set level. The Saudi riyal, for example, has been pegged at 3.75 to the US dollar for decades. Hong Kong pegs its dollar tightly to the US dollar through a currency board system. The United Arab Emirates also pegs the dirham to the US dollar. Pegging provides stability that helps trade and investment planning, since businesses know what their costs will be in foreign currency. The downside is that the central bank must hold large reserves of the anchor currency and stands ready to buy or sell its own currency to defend the peg, which can be costly if markets speculate against it.
Some countries sit between the two extremes with a managed float, where the rate mostly moves with the market but the central bank occasionally steps in to prevent excessive swings. India, China, and Singapore use variants of this approach.
What makes an exchange rate move?
For floating currencies, the rate shifts whenever the balance of supply and demand for a currency changes. These are the main drivers:
| Driver | Effect on currency |
|---|---|
| Higher interest rates | Tends to strengthen the currency, as investors seek higher yield |
| Rising inflation | Tends to weaken the currency, reducing purchasing power |
| Trade surplus (exports > imports) | Tends to strengthen the currency, as foreign buyers need to purchase it |
| Trade deficit (imports > exports) | Tends to weaken the currency, as the country sells its own currency to buy foreign goods |
| Political stability | Tends to strengthen the currency by attracting foreign investment |
| Political uncertainty or crisis | Tends to weaken the currency as investors move funds to safer assets |
| Strong economic growth | Tends to strengthen the currency by increasing investor confidence |
| Central bank intervention | Can move the currency sharply in either direction depending on the action taken |
In practice, these factors interact. A country might have high interest rates but also high inflation, and the net effect on the currency depends on which force is stronger at a given moment. This is why currency forecasting is notoriously difficult even for professional economists.
The mid-market rate versus the rate you are offered
The mid-market rate, also called the interbank rate, is the exact midpoint between the price at which currency dealers are willing to buy a currency and the price at which they are willing to sell it. It is the fairest representation of what a currency is actually worth at any moment, and it is the rate shown in financial news, on Google, and in tools like the currency converter below.
When you exchange money at a bank, a bureau de change, an airport kiosk, or through a money transfer app, you will almost never receive the mid-market rate. The provider adds a markup or spread to the rate, which is how they make money on the transaction. A bank might advertise no commission but quietly build 2 to 3 percent into the rate. An airport kiosk might take 5 to 8 percent. A specialist service like Wise typically charges far less, around 0.4 to 1 percent over mid-market, making it much closer to the true rate.
To understand exactly what you are paying, compare the rate you are being offered to the mid-market rate and calculate the percentage difference. That percentage is the real cost of the conversion, regardless of what the provider labels it. Our guide to the cheapest way to exchange currency walks through this comparison for every common method, from bank branches to ATMs to transfer services.
How to read a currency quote
When you see an exchange rate quoted, it usually looks like one of these forms:
- USD/CAD 1.3420: the slash separates base (USD) from quote (CAD), and the number tells you 1 USD = 1.3420 CAD.
- A bid and an ask: professional quotes show two prices, such as 1.3418 / 1.3422. The bid is the price dealers will pay to buy the base currency; the ask is the price at which they will sell it. The spread between them is the dealer's profit margin. Consumer-facing apps often hide this and show a single blended rate.
- Pip: in currency trading, the smallest standard price move is called a pip. For most pairs it is 0.0001, so a move from 1.3420 to 1.3421 is one pip. For pairs involving the Japanese yen, a pip is 0.01.
For everyday conversions you do not need to worry about pips or bid-ask spreads. What matters is: what rate am I being applied, and how does it compare to the mid-market rate right now?
Why some currencies consistently weaken
Some currencies lose value against the US dollar year after year while others stay stable or even appreciate. The difference usually comes down to a few underlying economic realities:
- Persistent trade deficits: when a country imports far more than it exports, it must sell its own currency to buy foreign goods, creating steady downward pressure.
- High inflation: a currency that buys less and less at home becomes less attractive to hold, so its exchange rate falls over time.
- Large external debt: countries that owe large amounts in foreign currency must keep earning enough foreign exchange to service the debt, and when reserves run low the currency comes under pressure.
- Political instability: governments that change unpredictably or pursue inconsistent policies deter foreign investment, reducing demand for the currency.
Conversely, economies with trade surpluses, low inflation, and stable governance tend to have strong or appreciating currencies. Japan and Switzerland are historically examples of this pattern, though even they experience significant swings around their longer trends.