Position Size Calculator: How to Calculate Forex Lot Size in Seconds
Pick a size that respects both your dollar risk and the margin headroom this calculator tells you to leave.
Margin Calculator: How Much Capital Does Your Trade Actually Lock Up
Most traders learn what margin is the day they hit a margin call. The Margin Calculator shows you, before you click buy, how much of your account a trade locks up — and how much breathing room you have before the broker closes it for you.
Leverage is the most misunderstood number in retail trading. Brokers advertise 500:1 like it is a feature. New traders read 500:1 and think they have access to half a million dollars. What they actually have is a smaller account that will be closed faster than they expect, the moment the equity drops below a threshold they have never bothered to read. The Margin Calculator is the tool that turns that abstract number into a concrete budget.
What Margin Actually Is
Margin is not a fee. It is a deposit. When you open a 1 lot EUR/USD position on a 100:1 leverage account, the broker is not lending you 100,000 dollars — they are letting you control 100,000 of notional exposure in exchange for ring-fencing roughly 1,000 dollars of your equity. That 1,000 is the required margin. It is yours, but it is frozen. If the position moves against you far enough that the rest of your equity is no longer enough to keep the position open, the broker liquidates the trade and you get the frozen margin back, minus the loss. That moment is called a margin call.
After ESMA's 2018 rules, most retail forex leverage in regulated jurisdictions was capped at 30:1 for major pairs. Brokers offshore still offer 500:1 or higher. The number changes; the math does not.
The Four Numbers and What They Mean
- Required Margin — the deposit the broker locks up for this one position. Smaller than you think, bigger than it feels when it stacks across five trades.
- Notional Value — the size of the position in dollars. This is what you are actually exposed to, not what you put up.
- Free Margin — the equity you have left for new trades or floating losses. The smaller this gets, the closer you are to a margin call.
- Margin Level — equity divided by required margin, expressed as a percentage. Most brokers issue a margin call around 100% and force-close around 50%.
How To Read The Result
If your margin used is more than 25% of your balance from a single trade, you are not trading, you are gambling. That is my line, not a regulator's, but it has held up over a decade of screen time. A healthy account stays well under 20% margin used across all open trades combined. That leaves room for losing positions to breathe before the broker decides for you.
The Mistake That Breaks Accounts
The classic blow-up story goes like this. Trader has a 1,000 dollar account and 500:1 leverage. They open 2 lots of EUR/USD because they can. Required margin is only 400 dollars, free margin is 600. Everything feels fine until the position drops 30 pips, which on 2 lots is 600 dollars of floating loss. Free margin is now zero. The next pip triggers the stop-out. Game over, in roughly the time it takes to make tea. Run the numbers in the calculator before you open the trade and the story does not happen.
Try the Margin Calculator
See exactly how much your next trade locks up — and how close it puts you to a margin call. Free, no signup.
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