What Free Margin is (definition)
Free Margin is the part of your account equity that is not tied up as margin for your currently open positions. In practical terms, it represents the available “buffer” that could still be used to absorb losses before an account safety process is triggered.
A useful simple model is:
- Equity: the value of your account including current profit/loss (unrealized) plus any cash.
- Used Margin: the margin amount your broker/platform has reserved to support open positions.
- Free Margin: Equity − Used Margin.
Different platforms may label items differently, but the core idea—equity available after reserving margin—stays the same.
How Free Margin works in forex (mechanics)
In forex, you typically post margin rather than paying the full notional value of a position. When you open a trade, the platform calculates a used margin amount based on the position’s size, leverage, and margin requirements.
At any moment after the position is open:
- Equity changes as the market moves, because your unrealized profit or loss updates.
- Used Margin usually stays constant for the life of the position unless the platform recalculates margin requirements.
- Free Margin therefore changes mainly because equity changes.
A quick worked example (assumptions stated):
- Assume equity is $10,000.
- Assume used margin for open trades is $2,000.
- Then free margin is $10,000 − $2,000 = $8,000.
If prices move against you so that unrealized loss reduces equity to $9,200 (with used margin still $2,000), free margin becomes $7,200. The key point is that Free Margin is not a fixed number; it moves with price-driven equity and with any platform-specific adjustments.
How Free Margin differs from related concepts
Free Margin is often discussed alongside nearby terms, but they do different jobs:
- Equity is the total account value including unrealized results. It can move up or down with price.
- Used Margin is the portion reserved to keep existing trades open.
- Margin Level is commonly defined as a ratio (for example, equity divided by used margin). It helps express “how close” you are to a threshold, even when account sizes differ.
- Margin Call / Liquidation are outcomes or events triggered when your Free Margin (or margin level) crosses rules set by the provider.
Free Margin is a quantity; the events are what may happen if it becomes too small.
Limitations and risks (what can go wrong)
Free Margin is useful, but it is not a guarantee of safety or predictability. Material limitations and failure modes include:
- Broker/platform rule differences: thresholds, how margins are calculated, and what happens next (margin call behavior vs. automatic account protection) vary by provider.
- Execution timing: if liquidity is low or volatility is high, price can move quickly between updates, and outcomes may deviate from what you expect at the last shown quote.
- Costs and adjustments: swaps/financing, fees, and credit/debit events can affect equity and therefore Free Margin.
- Model mismatch: your account interface might present values with specific rounding or additional buffers, so your manual calculations may differ slightly.
Because of these uncertainties, you generally can’t treat Free Margin as a precise countdown timer. It is better seen as a real-time snapshot under specific provider rules.
How to verify the facts on your account
To verify your understanding independently, check the definitions and formulas shown by your platform:
- Look for displayed fields such as equity, used margin, free margin, and any margin level or margin call thresholds.
- Confirm whether used margin is recalculated for your positions and how frequently values update.
- Compare the platform’s free margin figure with your own calculation using equity and used margin as presented.
If the platform provides a margin breakdown page or a “margin requirements” explanation, use that as the primary reference for provider-specific behavior and thresholds.