Margin, margin level and margin call — no mystery
Required margin is the part of your account the broker locks as collateral while the trade is open: notional value ÷ leverage. It's not a cost, it's a held deposit — you get it back on close. Free margin is what's left available to open more trades or absorb losses.
Margin level (equity ÷ used margin × 100) is your lifeline: when it drops too low (typically 100%), the margin call hits, a warning; if it keeps falling (say 50%), the broker closes positions automatically (stop-out) so you don't go negative. The more margin you commit, the less cushion you have against an adverse move.
The trap: high leverage makes required margin look tiny (moving $100,000 with $1,000), which invites opening huge positions. But low margin doesn't reduce your risk — it just lets you over-risk. Learn why in leverage and margin, and control real risk with position sizing, not with whatever the broker allows.