Direct answer
To calculate when a forex margin call happens, you generally work from either (1) margin level or (2) free margin. The most common starting point is margin level:
- Margin level (%) = (Equity ÷ Used Margin) × 100
- A margin call is triggered when this margin level falls below the broker’s required threshold for the account.
If you know (a) your current equity, (b) the used margin, and (c) the broker’s margin-call threshold, you can determine whether you are above or below the trigger.
Explanation (inputs and how the calculation works)
Key terms
- Equity: your account value including unrealized profit/loss (often: balance + floating P/L).
- Used margin: the margin currently tied up to keep your open positions running.
- Free margin: equity minus used margin. A common definition is:
- Free margin = Equity − Used Margin
- Margin call / stop-out: actions taken by the broker when margin metrics fall too low. Exact thresholds and actions vary.
Margin-level method
- Compute Used Margin for your open positions (how it is computed can vary by instrument and broker rules).
- Compute Equity using the definition above.
- Calculate:
- Margin level (%) = (Equity ÷ Used Margin) × 100
- Compare to the broker’s margin call threshold (for example, “margin call at X%”).
If your calculated margin level is below the threshold, a margin call would be expected under that rule set.
Free-margin cross-check
Even if you use margin level as the main method, you can cross-check with free margin:
- Free margin = Equity − Used Margin
- If free margin approaches zero or a broker-defined limit, the account is nearing the point where forced actions (like stop-out) can occur.
Because brokers define triggers differently, a free-margin number that “looks low” does not always map to an exact margin call without the broker’s specific limits.
Example checks (with clear assumptions)
Assume these are known from your platform:
- Equity = 900
- Used margin = 1,000
- Your broker requires a margin call threshold of X% (you must use your broker’s value).
Step 1: Margin level = (900 ÷ 1,000) × 100 = 90%.
Step 2: If X% is, for example, 100%, then 90% is below the threshold, so the margin call condition is met under that rule.
For a free-margin check:
- Free margin = 900 − 1,000 = −100. A negative free margin indicates equity is below used margin, which usually means the account is in a critical state. However, the exact broker behavior (margin call vs stop-out) still depends on the broker’s rule set.
Limitations and uncertainty
- Broker rules vary: margin call thresholds, how used margin is calculated, and when actions occur (margin call vs stop-out) are not universal.
- Platform timing matters: calculations can update on price changes, valuation settings, and account type.
- This is an estimate without your exact parameters: you must use your broker’s reported equity, used margin, and margin call level to compute a specific trigger.
For an independently verifiable result, rely on the definitions above and the exact threshold and margin figures your platform displays, then recompute margin level and/or free margin to see whether you cross the trigger condition.