Direct Answer

A margin call happens when your account equity drops to or below your broker's required margin level, and you must deposit more money or watch positions get closed automatically. In plain terms, it means your open trades are losing faster than your account balance can support. Most brokers trigger a warning when the margin level hits 100% — where equity equals the margin locked up in open trades. If losses continue, a stop-out liquidates your biggest losers. You avoid this by risking only 1–2% per trade, using modest leverage, and keeping a comfortable free-margin cushion at all times.

How the Margin Level Math Works

Your margin level is a simple ratio: (equity ÷ used margin) × 100. Suppose you have a $1,000 account and open a position tying up $200 of margin. If the trade loses $700, your equity is $300 and your margin level is 150% ($300 ÷ $200). At 100%, the broker warns you; below that, stop-outs begin. The key insight is that losses shrink the numerator while the denominator stays locked, so margin level can collapse quickly during a sharp move. Watching this number is more useful than watching your balance, because it shows your real distance from forced liquidation.

The Three Habits That Trigger Margin Calls

Margin calls almost never come from bad luck — they come from three repeatable mistakes. First, oversized positions: risking 10–20% of the account on one trade means a single bad day can halve the account. Second, adding to losing trades ('averaging down'), which increases used margin while equity is falling — the fastest route to a stop-out. Third, trading through high-impact news with full size, where spreads widen and slippage multiplies losses. A fourth, quieter killer is simply ignoring the margin level readout on the platform until the warning email arrives. Professionals treat margin level like a fuel gauge: they plan position sizes so it rarely drops below 500%.

Practical Steps to Stay Clear of Margin Calls

Start with position sizing: size each trade from its stop-loss distance so a full loss costs 1–2% of the account — never guess the lot size. Use leverage conservatively, since high leverage turns a normal losing streak into a margin call. Set a stop loss on every trade, because an open-ended loss is what drags equity toward the danger zone. Keep at least half your margin free as a volatility buffer, and never add funds to 'rescue' a trade that already hit your stop — that is throwing good money after bad. For a deeper method, see /post/position-sizing-risk-management-guide.

Frequently Asked Questions

What is the difference between a margin call and a stop-out? A margin call is the warning — your broker tells you to add funds or cut exposure. A stop-out is the action: the broker closes your positions to prevent a negative balance. How much free margin should I keep? Many experienced traders keep their margin level above 300–500% — most of the account stays untied in open trades. The more volatile the market, the larger the buffer. Can a margin call wipe out my whole account? Almost. Stop-outs usually close trades before the balance goes negative, but gaps and slippage can still leave the account nearly empty. Never trade money you cannot afford to lose.