Margin is an amount reserved on the account balance to back the open trade. Once the position is closed, this amount becomes available again.
How do I calculate my margin?
Example 1
Let's assume your account balance is €10,000, and you want to invest €200 in EUR/USD with a 30 multiplier/leverage. When you open your position, your margin will be calculated as follows:
Margin=Investment Amount
In our example: Margin=€200
When you open your trade, you should remember to have some available or free margin on your account. Free margin is the difference between your current account balance and your margin already being used:
Free Margin=Account balance–Used Margin
How much margin will be free for opening new positions if my account balance is €10,000, and the used margin is €200?
In this case, your free margin will be €10,000-€200=€9,800, which you can use to open new trades.