The profit and loss rates when you leverage your trade

As mentioned, your margin is your investment. Accordingly, you invest a margin of $1,000 for a contract of $100,000. This is a 1:100 rate. If the currency exchange rate moved, for example, 0.5% that would be a 50% change on your margin! Since the contract is 100 times the margin, then the change of 0.5% becomes 100 times bigger, to 50%.