Currency conversion and your account base currency: what it costs and how to choose

Your account base currency is the currency your trading balance is held in: euros, pounds, US dollars or another currency the broker offers. Every deposit, trade result, swap, commission and withdrawal that is in a different currency has to be converted into it, and each conversion can carry a markup. Choosing the currency you earn and bank in usually removes most of those conversions, and it also stops your balance moving with an exchange rate you never meant to trade.

Two meanings of "base currency"

The phrase causes confusion because it means two different things in forex.

• The base currency of a pair is the first currency in the quote. In EUR/USD, the euro is the base currency and the US dollar is the quote currency. The price tells you how many units of the quote currency one unit of the base buys. The glossary entry on base currency and the currency pairs guide cover this meaning.
• The base currency of an account, also called the account currency or deposit currency, is the currency your trading account is denominated in. It is chosen when the account is opened and is usually fixed afterwards.

This guide is about the second meaning, but the first one matters to it, because the quote currency of each pair decides what currency your profit and loss arrives in.

Where conversion happens

Conversion is not a single event. It happens at several points in the life of an account, and most traders only notice the first.

Money in and money out

If you send euros from your bank to a US dollar trading account, someone converts them: your bank, the payment provider or the broker. The same happens in reverse on withdrawal. Each leg is usually priced at a rate a little worse than the mid-market rate, and the difference is the conversion margin. The hidden broker fees guide covers deposit and withdrawal charges in detail, so this guide focuses on what happens inside the account.

Trade profit and loss

Every forex trade produces its profit or loss in the quote currency of the pair.

• EUR/USD, GBP/USD, AUD/USD: P&L is in US dollars.
• USD/JPY, EUR/JPY, GBP/JPY: P&L is in Japanese yen.
• EUR/GBP: P&L is in pounds.
• USD/CHF, EUR/CHF: P&L is in Swiss francs.
• USD/CAD: P&L is in Canadian dollars.

If the quote currency is not your account currency, the broker converts the result. Some brokers convert when the trade closes, others convert floating P&L continuously so your equity is always shown in account currency. Either way, the rate used, and whether it includes a markup, is set out in the broker's terms or fee schedule.

Margin

Margin is held in your account currency, but it is calculated on the notional value of the position, which is in the pair's base currency. So the broker converts the notional into your account currency, then applies the leverage ratio. This affects how much free margin you have, and it means the margin on the same position changes as exchange rates move, even if the pair you are trading does not. The leverage and margin guide and the margin calculator cover the basics.

Swaps and commissions

Overnight swaps are calculated in the instrument's currency and converted. Commissions may be quoted in dollars, euros or another currency and converted to yours. Individually these conversions are small; added up over a year of active trading they are not nothing. The swap and overnight financing guide explains the swap itself.

CFDs on other markets

A CFD on a US index or share is priced in dollars, a German index in euros, a Japanese index in yen, gold usually in dollars. Every one of these produces P&L that has to be converted into your account currency. On share CFDs, some brokers charge an explicit conversion fee on each trade's result. The CFD guide covers how these products are priced.

How P&L conversion works: a worked example

The figures below are illustrative. Exchange rates are rounded for clarity and are not current prices.

Sofia has a euro account. She buys 1 standard lot of USD/JPY at 150.00 and closes it at 150.50, a gain of 50 pips.

• On USD/JPY one pip is 0.01 yen per dollar. On 100,000 dollars of notional, one pip is worth 1,000 yen.
• 50 pips × 1,000 yen = 50,000 yen profit.
• The broker converts 50,000 yen to euros. If EUR/JPY is at 162.00, that is 50,000 ÷ 162 = about €308.64 at the mid rate.
• If the broker applies a 0.5% conversion markup, Sofia receives about €307.10. The markup costs her about €1.54.

The same trade with a loss works the same way in reverse: the yen loss is converted into a euro debit. Whether the markup applies to losses as well as gains depends on the broker; usually it does, because a conversion is a conversion.

A small markup on one trade is not dramatic. But it applies to every trade on a pair whose quote currency differs from your account currency, so for active traders it compounds into a real cost, and it belongs in any comparison of trading costs.

Note also that the pip value in your account currency moves with the conversion rate. On Sofia's euro account, 1,000 yen per pip is worth more euros when the yen is strong and fewer when it is weak. The pip value calculator lets you set your account currency so the figure you see is the one that actually lands in your balance.

Margin in a different currency: a worked example

Again, illustrative rates and the ESMA retail leverage limit of 30:1 for major pairs.

Tom has a euro account. He wants to open 1 lot of GBP/USD. The notional is £100,000.

• Margin in the pair's base currency: £100,000 ÷ 30 = £3,333.33.
• Converted to euros at an illustrative EUR/GBP of 0.8500: £3,333.33 ÷ 0.85 = about €3,921.57.

If he opened 1 lot of EUR/USD instead, the notional is €100,000 and the margin is simply €100,000 ÷ 30 = €3,333.33, with no conversion at all, because the base currency of the pair matches his account.

If the pound strengthens against the euro while Tom's GBP/USD trade is open, the euro value of his margin requirement rises, even if GBP/USD itself has not moved. On a well-funded account this is a minor effect. On an account running close to its limits, it is one more way for margin level to fall without the trade going against you. The margin call and stop-out guide explains why that matters.

The exposure nobody mentions: your balance is a currency position

This is the part of account currency that most traders never think about, and it can be larger than every fee combined.

If you earn and spend euros but hold a US dollar trading account, your entire balance is a dollar position. When the dollar weakens against the euro, your balance is worth fewer euros, even if you have not placed a trade.

Illustrative example: Luca deposits €10,000 into a dollar account when EUR/USD is 1.1000, so his balance is $11,000. He trades for a year and finishes exactly flat, still $11,000. But EUR/USD is now 1.2000. When he withdraws, $11,000 converts to about €9,166.67. He has lost about €833, roughly 8% of his deposit, from a currency move he never chose to trade, before any conversion fees.

It could just as easily have gone the other way: if EUR/USD had fallen to 1.0000, his $11,000 would have come back as €11,000. That is the point. Holding the account in a currency you do not use adds a source of gains and losses unrelated to your trading. It makes your results harder to read, and it means a strategy that is break-even in dollars may be losing or winning in the currency you actually live on.

Some traders choose this exposure deliberately. Most simply picked the first option on the sign-up form.

How to choose an account currency

There is no universal right answer, but there is a sensible default and a few reasons to depart from it.

The default: match your bank account

Choose the currency of the bank account you deposit from and withdraw to, which for most people is also the currency they earn and spend. A euro earner with a euro bank account opens a euro trading account; a UK resident paid in sterling opens a sterling account. This:

• removes conversion on every deposit and withdrawal;
• removes the hidden currency exposure on your whole balance;
• means your results, statements and annual cost reports are in the currency you think in.

P&L on pairs quoted in other currencies is still converted, but only the result of each trade, not the whole balance twice.

When a different currency might make sense

• You earn or bank in that currency. Someone paid in dollars, with a dollar bank account, has every reason to use a dollar account even if they live in the euro area.
• Your home currency is not offered. Brokers typically offer a handful of major currencies. If yours is not one of them, pick the one that involves the fewest conversions for your situation, and know that the balance carries currency exposure.
• You trade almost only one quote currency. A trader who exclusively trades dollar-quoted pairs and instruments might reduce per-trade conversions with a dollar account, but they reintroduce conversion on deposits, withdrawals and the balance itself. For most retail traders the balance exposure outweighs the per-trade saving. Run the numbers for your own case.

What to check before opening

• Which account currencies the broker offers for the account type you want. Raw-spread and standard accounts do not always offer the same list.
• The conversion rate the broker uses for P&L and swaps, and any markup or explicit fee, which should be in the fee schedule or terms.
• Whether you can hold more than one account in different currencies under the same login, and whether transfers between them are converted at a markup.
• Whether the account currency can be changed later. Usually it cannot; you open a new account and move the funds, with a conversion.

Our guide to broker account types covers the wider choice of account, and the how to choose a forex broker guide puts currency options alongside the other things worth checking.

Account currency and position sizing

Risk management happens in your account currency. If you risk 1% of a €5,000 account, that is €50 per trade, and your position size has to be worked out from the stop distance and the pip value in euros, not in the pair's quote currency.

Illustrative example: a €5,000 account, 1% risk (€50), a 25-pip stop on GBP/USD. One pip on one standard lot of GBP/USD is $10. At an illustrative EUR/USD of 1.1000 that is about €9.09 per pip per lot. Risk per lot over 25 pips is about €227. €50 ÷ €227 = about 0.22 lots.

Use the position size calculator with your account currency selected, and read the position sizing guide for the method. A common error is to size a trade as if the pip value were in your account currency when it is not; on yen or Swiss franc pairs the mistake can be material.

Reading your statements

Your trade history should show P&L both in the instrument's currency and in your account currency, or at least the converted figure. Compare a few trades:

1. Take the pips gained or lost and the trade size, and work out the P&L in the quote currency.
2. Divide or multiply by the exchange rate at the close to get the account-currency figure at the mid rate.
3. Compare with what was booked. The gap, if consistent, is the conversion markup.

Do the same with a deposit and a withdrawal: the amount sent, the amount credited, and the published mid rate on that day. Together these checks tell you what currency conversion really costs you, which is often more than the fee schedule makes obvious. Recording them in your trading journal makes it easy to track over time.

Common mistakes

• Accepting the default currency. Many sign-up forms default to US dollars. If you do not bank in dollars, that choice costs you on every transfer and adds currency exposure to your balance.
• Thinking "I only trade EUR/USD, so I need a dollar account." P&L on EUR/USD is in dollars and will be converted into a euro account, but only the result is converted. A dollar account instead converts your whole balance, twice.
• Ignoring balance exposure. A flat year of trading in a foreign-currency account can still be a losing year in your own currency.
• Sizing positions in the wrong currency. Pip value must be in your account currency for risk calculations to be right.
• Not checking the conversion markup. It may be small per trade, but it applies to every trade, swap and commission in another currency.
• Opening several accounts in different currencies without a reason. Each transfer between them is another conversion.

None of this changes the underlying risk of leveraged trading. Most retail CFD accounts lose money, as our risk warning sets out, and conversion costs are one more small drag on results that have little room for avoidable losses.

Frequently asked questions

What is an account base currency in forex?

It is the currency your trading account is held in, chosen when you open it. Your balance, equity, margin and results are all shown in that currency, and anything in another currency, such as P&L on pairs quoted in yen or dollars, is converted into it.

Can I change my trading account currency?

Usually not on an existing account. Most brokers require you to open a new account in the new currency and transfer the funds, which involves a conversion. Some brokers let you hold several accounts in different currencies under one profile.

Does my account currency affect my trading results?

Yes, in two ways. Conversion markups on P&L, swaps and commissions reduce results slightly. And if the account is in a currency you do not use, your whole balance moves with that exchange rate, which can add gains or losses that have nothing to do with your trades.

Is a US dollar account better because forex is priced in dollars?

Not for most people who earn and bank in another currency. A dollar account saves the conversion on the result of dollar-quoted trades, but adds conversion on every deposit and withdrawal and turns your balance into a dollar position. Matching your bank currency is the simpler default.

How do brokers convert profit and loss into my account currency?

They take the P&L in the pair's quote currency and convert it at their exchange rate, either when the trade closes or continuously while it is open. That rate may be the mid-market rate or may include a markup. The broker's terms or fee schedule should say which.

Does account currency matter for margin?

Yes. Margin is calculated on the position's notional value in the pair's base currency and converted into your account currency. If the pair's base currency is the same as your account currency, no conversion is needed; otherwise the margin requirement changes as that exchange rate moves.