Required margin is the deposit your broker locks up to hold a leveraged position open. It is a fraction of the position's full value, set by your leverage. This calculator shows both numbers so you can see exactly how much of your account a trade ties up.
Notional is expressed in USD. Margin equals notional divided by leverage. Higher leverage frees up more of your balance but does nothing to reduce the risk of the position itself.
The formula
Margin is the full value of the position divided by your leverage:
Required margin = (lots x contract size x price) / leverage
One standard lot of EUR/USD at 1.1000 is a $110,000 position. At 1:100 leverage the broker only holds $1,100 of your money to open it; at 1:30 it holds $3,667. The position - and its risk - is identical either way. Leverage changes the deposit, not the exposure, which is the point traders most often miss in how leverage works.
Why margin is not your risk
A common and dangerous mistake is treating the margin figure as the amount at risk. It is not. Your risk is set by your stop-loss distance and position size, not by the deposit the broker parks. You can lose far more than the margin if you trade without a stop. Margin only tells you how much buying power a trade consumes, which matters for how many positions you can hold at once and how close you sit to a margin call.
Free margin is the number to watch: the margin here is locked while the trade is open. What is left - your free margin - is the buffer that absorbs open losses. Run it too thin across several positions and a normal drawdown can trigger a stop-out. Keep risk per trade small and margin rarely becomes the constraint.
Feel leverage without the risk
The safest place to learn how leverage and margin behave is a backtest, where you can set the leverage, open real-sized positions, and watch free margin move - all without a live account on the line.
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Margin calculator FAQ
How do you calculate required margin in forex?
Multiply your lot size by the contract size and the current price to get the notional value, then divide by your leverage. One standard lot of EUR/USD at 1.1000 is $110,000 notional; at 1:100 leverage the required margin is $110,000 / 100 = $1,100.
Is margin the same as risk?
No. Margin is only the deposit the broker locks to open a position - it is not the amount you can lose. Your actual risk is set by your stop-loss distance and lot size. Without a stop you can lose far more than the margin posted.
Does higher leverage mean more risk?
Higher leverage lowers the margin a position needs, which frees up balance and can tempt oversizing - that is where the danger is. The leverage itself does not change a position's risk; the lot size and stop do. Used with disciplined sizing, high leverage simply means more free margin.