Direct answer
Required margin is the amount of account equity that must be set aside (reserved) by a forex provider to support a specific leveraged position. It functions like a “capacity requirement”: if you do not have enough free equity to cover required margin, the platform may not allow the position to open, or it may later reduce available room as losses increase.
Mechanism and definition
A useful mental model is to split your account into two related parts:
- Equity: your account value after accounting for profit and loss (P&L). In practice, equity moves as the market moves.
- Free margin: the equity that is not already reserved for open positions.
For each open position, the platform calculates a required margin based on the trade size and the applicable leverage/margin rules. The key point is that required margin is not the same as profit or loss; it is a reserved amount used to determine whether the account has enough “unused” equity to keep risk within limits.
Assumption for examples: because different providers use different contract specifications and formulas, treat the example below as a simplified illustration rather than a provider-specific calculation.
Simple example (illustrative)
- You open a leveraged position.
- The platform determines that opening it needs a certain required margin.
- That required margin is subtracted from free margin.
- If the position moves against you, equity can drop.
- As equity drops, the same required margin stays “reserved,” so the ratio between equity and required margin worsens.
This is why required margin is central to leverage: leverage increases position size, which typically increases the required margin for that size, while also making account equity more sensitive to moves.
Adjacent concepts: what required margin is not
Required margin is often confused with nearby terms:
- Margin balance vs. equity: equity changes with P&L; margin figures are tied to position requirements.
- Spread and commissions: these are costs and can influence P&L, but they are not the definition of required margin.
- Margin level: this is a ratio formed from equity and required margin. Required margin itself is an input; margin level is an output measure used to manage risk.
Limitations and failure modes
Required margin does not guarantee outcomes, because several practical limitations can change what happens after a position is opened:
- Market moves can outpace your buffer. If losses reduce equity, required margin stays in place while free margin shrinks, increasing the risk of protective actions.
- Calculations can vary by provider and product. Different contract sizes, leverage rules, and margin treatment (for hedging, offsetting, or different instrument types) can change required margin.
- Costs affect equity even if they do not change required margin directly. Financing charges, commissions, and spreads can alter equity over time, indirectly affecting how close you are to risk limits.
A common failure mode is insufficient equity: even if you had enough free margin at the moment of opening, later price movement can lower equity enough that the account no longer satisfies the margin constraints.
Verification and next question
To independently verify required margin concepts for your situation, compare these items in your provider’s platform documentation:
- How required margin is calculated for your instrument and position size.
- How equity and free margin are defined on the account.
- How the platform responds when equity falls relative to required margin (for example, what thresholds exist and what actions can occur).
If you want, tell me which instrument type you mean (spot forex vs. another FX product) and what provider/platform you use, and I can outline the exact fields and definitions to look for in their docs—without needing real-time prices.