Forex Margin Calculator

A forex margin calculator shows how much of your account must be set aside as collateral to open a position of a given size. Required margin is the trade’s notional value divided by the leverage, converted into your account currency. For example, a notional value of $108,500.00 with a required margin of $3,616.67 is a ratio of exactly 30. That is leverage of 1:30, or a margin requirement of about 3.33% of the position’s value.

What goes in and what comes out

A margin calculation depends on four things:

• Currency pair. The first currency in the pair, the base currency, sets what the position is denominated in.
• Trade size. This is measured in units or lots. One standard lot is 100,000 units of the base currency, a mini lot is 10,000 and a micro lot is 1,000.
• Leverage. This is the ratio your broker or funded account allows on that instrument, such as 1:30, 1:50 or 1:100.
• Account currency. The margin is held in your deposit currency, so the notional value has to be converted into it.

The output has two parts. Notional value is the full size of the position in your account currency. Required margin is the slice of your equity that is locked while the trade is open.

The formula

Required margin = (trade size in units × base-to-account conversion rate) ÷ leverage

The conversion step depends on how your account currency relates to the pair. The examples below use a USD account, 1 standard lot and 1:100 leverage, with hypothetical exchange rates rather than current quotes.

Cross pairs are where people slip. Margin follows the base currency, so a EUR/GBP position in a USD account is valued at the EUR/USD rate, not the EUR/GBP price. When the account currency is the base, as in USD/JPY for a USD account, the conversion rate is 1 and the notional value equals the unit count.

The same arithmetic works in reverse. The margin percentage is 1 divided by the leverage:

• 1:30 is 3.33%
• 1:50 is 2%
• 1:100 is 1%
• 1:500 is 0.2%

What 1:100 leverage means in practice

At 1:100, every $1 of margin supports $100 of position, so $1,000 of equity could in theory carry $100,000 of exposure, roughly one standard lot of a USD-base pair. That ceiling is not a plan. The first adverse move would push the account toward a margin call, because almost no free margin would be left to absorb losses. The same account at 1:30 tops out at $30,000 of notional value. With $100 at 1:500, the ceiling is $50,000.

Leverage limits are often set by regulation rather than by the broker alone. In the European Union, ESMA rules in place since 2018 cap retail leverage at 1:30 on major currency pairs and lower on other pairs. In the United States, NFA and CFTC rules allow 50:1 on major pairs and 20:1 on others. Prop firms set their own leverage for funded accounts, so the right input is whatever your account terms state.

Used margin, free margin and margin level

Once a trade is open, the required margin becomes used margin. Three related figures describe account health:

• Equity = balance + floating profit or loss on open trades.
• Free margin = equity − used margin. This is what remains for new positions and for absorbing losses.
• Margin level = (equity ÷ used margin) × 100%.

Both are calculated from equity, not balance, so a losing position shrinks them even though your balance has not changed.

Margin calls and stop-outs

Brokers set two thresholds on margin level. At the margin call level, the broker warns you or blocks new trades. At the stop-out level, it starts closing positions automatically, usually the largest loser first, so that losses do not exceed your deposit. The exact percentages differ by broker and account type.

Here is a worked example with assumed figures: a $2,000 USD account, 1 lot of EUR/USD with $1,100 used margin at 1:100, a pip value of $10, and a hypothetical stop-out at 50%.

1. At entry, equity is $2,000 and the margin level is 182%.
2. After a 50-pip move against you, equity is $1,500 and the margin level is 136%.
3. A 50% margin level means equity of $550. That leaves room for a $1,450 loss, or about 145 pips, before positions are closed. This ignores spread and commission.

Halving the position to 0.5 lots doubles the pip distance to stop-out, because both the margin and the pip value fall by half. Read the margin result alongside your stop-loss distance.

Using the result to size a trade

The required margin tells you whether a trade fits in your account, not whether it is sensible. Risk per trade comes from position size multiplied by stop distance and pip value. A practical sequence:

1. Decide the amount you are willing to lose on the trade and set your stop distance.
2. Convert that into a lot size with the position size calculator, using pip values from the pip calculator.
3. Run that lot size through the margin calculator to confirm how much margin it locks.
4. Check that the remaining free margin can absorb the stop-loss plus a buffer, without the margin level approaching your broker’s thresholds.
5. Estimate outcomes at your targets with the forex profit calculator.

Lower leverage does not reduce the profit or loss of a given lot size. It only raises the margin locked per lot. The real risk control is the lot size.

What the calculation leaves out

• Rate changes. Margin moves with the conversion rate, rising if the base currency strengthens against your account currency.
• Trading costs. Spreads, commissions and overnight swaps reduce equity but are not in the margin figure.
• Broker-specific rules. Some brokers use tiered margin that rises with position size, raise margin around major news or weekends, or reduce margin on hedged positions.
• Instrument differences. Minor pairs, exotics, metals and CFDs often carry lower leverage than majors, so one leverage input may not fit every symbol.
• Funded account rules. Prop firm daily loss and drawdown limits can end a trade long before any margin threshold is reached.