Market StructureBase
Base Currency
The first currency in a pair - the one being bought or sold, and the unit in which position size is measured.
What Base Currency means
In any currency pair the base currency is written first, and the exchange rate tells you how many units of the second currency one unit of the base is worth. Buying the pair means buying the base and simultaneously selling the quote currency; selling the pair does the reverse. Position size in forex is always expressed in units of the base currency, which is why a standard lot of EUR/USD is 100,000 euros rather than 100,000 dollars, and why lot sizes are constant across pairs while notional values in dollars differ.
The term has a second, unrelated meaning that causes confusion: the base currency of a trading account is the currency the account is denominated in, such as USD, EUR or GBP. Profits, losses and margin are converted into that account currency, sometimes with a conversion charge. When reading broker documentation, check which sense is meant, because the account base currency has no necessary relationship to the base currency of the instruments being traded.
Worked example
In GBP/USD at 1.2700, sterling is the base currency, so buying one standard lot means buying 100,000 pounds and selling 127,000 US dollars.
Related terms
- Quote CurrencyThe second currency in a pair - the one the exchange rate is expressed in and in which profit and loss accrue.
- Currency PairTwo currencies quoted against each other, expressing how much of the second currency one unit of the first is worth.
- Standard LotA position of 100,000 units of the base currency, the benchmark trade size in forex.
- Contract SizeThe number of units of the underlying instrument represented by one lot or one contract.
- Currency Conversion FeeA charge applied when converting between the account's base currency and the currency of a trade or transfer.
Frequently asked questions
What does Base Currency mean in forex trading?
The first currency in a pair - the one being bought or sold, and the unit in which position size is measured.
How does Base Currency work in practice?
The term has a second, unrelated meaning that causes confusion: the base currency of a trading account is the currency the account is denominated in, such as USD, EUR or GBP. Profits, losses and margin are converted into that account currency, sometimes with a conversion charge. When reading broker documentation, check which sense is meant, because the account base currency has no necessary relationship to the base currency of the instruments being traded.
What is an example of Base Currency?
In GBP/USD at 1.2700, sterling is the base currency, so buying one standard lot means buying 100,000 pounds and selling 127,000 US dollars.
Trade with a regulated broker
Understanding the terminology is the cheap part. The expensive part is choosing a counterparty whose execution, financing and withdrawal behaviour match what the marketing implies. Every broker below has been reviewed with a funded live account, and each review states which legal entity and which regulator applies to the account you would actually open.
Check the licence on the regulator's own register before you deposit — our regulators directory explains what each authority enforces, from leverage caps to compensation limits.