When a Margin Call = 70% and Stop Out level = 50%, this means that once your Account Equity = Required margin x 70% you’ll get a Margin Call in the form of a Warning.
When your Account Equity = Required margin x 50% your trades will be closed automatically starting from the least profitable one.
Required Margin = (Market Quote for the pair * Lots) / Leverage.
Example: You want to open 0.1 lot (10 000 base currency) lots of EUR/USD at the current market quote of 1.1500 and with a leverage level of 1:400
Required Margin = (1.1500 * 10 000) / 400 = $28.75
Margin Call = Account equity has become equal to required margin.
Account equity = available not used in trade funds + floating profits from still open trades – floating losses from still open trades