Why Are Currencies Traded in Pairs?
Currency Pair Basics

Currencies are traded in pairs because the value of one currency must always be measured against another.

Unlike a physical product with a standalone price tag, a currency does not have one fixed value on its own. Its value changes depending on which other currency it is being compared with. This is why the foreign exchange market uses pairs such as EUR/USD, GBP/USD and USD/JPY.

A currency pair shows the exchange rate between two currencies. It tells you how much of one currency is associated with one unit of another currency.

This article explains why currency pairs are used, how they are structured and how to read a forex quotation.

Why Currencies Need to Be Compared

Every currency has value only in relation to another currency.

For example, the euro may be compared with the US dollar, the British pound may be compared with the Japanese yen, or the Australian dollar may be compared with the Canadian dollar.

A person travelling from Europe to the United States may need to exchange euros for US dollars. A company in the United Kingdom may need to pay a supplier in Japanese yen. In both cases, one currency is exchanged for another at an available exchange rate.

This is the central idea behind forex.

The market does not quote a currency as simply “one euro” or “one US dollar.” Instead, it shows the relationship between the two currencies involved in the exchange.

What is a Currency Pair?

A currency pair is a quotation made up of two currencies.

The first currency is called the base currency. The second currency is called the quote currency.

For example:

• EUR/USD
• GBP/USD
• USD/JPY
• AUD/USD
• EUR/GBP

Each currency is represented by a three-letter code.

For example:

• EUR = Euro
• USD = US dollar
• GBP = British pound
• JPY = Japanese yen
• AUD = Australian dollar
• CHF = Swiss franc

A currency pair shows how much of the quote currency is associated with one unit of the base currency.

Base Currency and Quote Currency

Understanding the order of the currencies is an important part of reading forex prices.

How to Read a Currency-Pair Quote

Consider the following example:

EUR/USD = 1.1000

This quotation means that one euro is associated with 1.1000 US dollars.

In this example:

• EUR is the base currency.
• USD is the quote currency.
• 1.1000 is the exchange rate.

Another example:

GBP/JPY = 190.00

This means that one British pound is associated with 190.00 Japanese yen.

The pair format gives the exchange rate a clear reference point. Without a second currency, there would be no way to show what the first currency is being measured against.

Why Pair Order Matters?

The order of currencies in a pair is not random.

EUR/USD and USD/EUR describe the same two currencies, but they are quoted in the opposite direction. The price will therefore look different.

For example, if EUR/USD is shown as 1.1000, USD/EUR would show the inverse relationship. The precise figure may vary depending on the pricing format and applicable spread.

The order of the pair changes the way the price is read:

• EUR/USD shows the euro in relation to the US dollar.
• USD/EUR shows the US dollar in relation to the euro.

This is why it is important to check which currency appears first and which appears second before reading a quotation.

Buying and Selling Within a Currency Pair

A currency-pair transaction always involves two sides.

When a person places a buy order on a currency pair, the order is linked to buying the base currency and selling the quote currency.

When a person places a sell order on a currency pair, the order is linked to selling the base currency and buying the quote currency.

For example, with EUR/USD:

• A buy order is linked to buying euros and selling US dollars.
• A sell order is linked to selling euros and buying US dollars.

This is another reason currencies are quoted in pairs. A currency transaction cannot involve only one currency. One currency is always exchanged against another.

Bid and Ask Prices

A forex platform commonly displays two prices for a currency pair.

The difference between these two prices is known as the spread.

For example, a platform may display:

EUR/USD
Bid: 1.1000
Ask: 1.1002

The difference between the bid and ask price is the spread.

Spreads can vary depending on the currency pair, market activity, liquidity and platform conditions.

Direct Pairs and Cross Pairs

Currency pairs are often grouped according to whether they include the US dollar.

Why Exchange Rates Change

Currency-pair prices can change throughout the business week while the relevant market is open.

Exchange rates are influenced by many factors, including:

• Interest-rate decisions
• Inflation data
• Employment reports
• Economic activity
• Central-bank communication
• International trade data
• Government policy
• Political developments
• Geopolitical events
• Market sentiment

For example, economic information from the euro area may influence EUR-related pairs, while information from the United States may influence pairs that include the US dollar.

However, currency markets can respond differently to the same event depending on wider market conditions and expectations. No single factor determines the movement of a currency pair.

Currency Pairs and International Exchange

Currency pairs are not used only on trading platforms.

They are also relevant to international business, travel, banking and cross-border payments.

For example:

• A business may need to convert one currency to pay an overseas supplier.
• A traveler may exchange their local currency before visiting another country.
• A bank may process payments involving multiple currencies.
• A company with international operations may receive and make payments in different currencies.

In each situation, the exchange involves two currencies. The currency-pair format provides a standard way to display the relationship between them.