What Is Margin in Forex? Understanding Margin Requirements
Margin is one of the most misunderstood concepts in forex trading. New traders often confuse it with a fee, a cost, or even leverage itself. It's none of those things.
Margin is a deposit. It's the amount of money your broker holds as collateral while you have a trade open. Think of it as a good-faith payment — you're not paying it to anyone, and you get it back when the trade closes. But if the trade moves against you far enough, that margin is what stands between you and a forced liquidation.
Margin vs Leverage: The Relationship
Margin and leverage are two sides of the same coin. Leverage determines how much buying power you get. Margin is the actual capital you need to put up.
The math is straightforward:
Margin Requirement = Position Size / Leverage
With 1:100 leverage, you need 1% of the position value as margin. With 1:50, you need 2%. With 1:500, you need 0.2%.
| Leverage | Margin Requirement | Capital Needed for 1 Standard Lot (100,000 units) |
|---|---|---|
| 1:50 | 2% | $2,000 |
| 1:100 | 1% | $1,000 |
| 1:200 | 0.5% | $500 |
| 1:500 | 0.2% | $200 |
So when someone says they're trading with 1:100 leverage, what they're really saying is: "My broker requires 1% margin to open a position."
Types of Margin You Need to Know
There are several margin-related terms you'll encounter on your trading platform. Each one matters.
Required Margin (or Initial Margin) The amount locked up when you open a single trade. If you buy 1 standard lot of EUR/USD at 1:100 leverage, your required margin is approximately $1,000 (depending on the exchange rate).
Used Margin The total margin currently tied up across all your open positions. If you have three trades open requiring $500, $800, and $300 respectively, your used margin is $1,600.
Free Margin The money available in your account to open new trades. Calculated as:
Free Margin = Equity - Used Margin
This is the number that determines whether you can open additional positions. If your free margin hits zero, you can't open anything new.
Equity Your account balance adjusted for unrealised profit or loss on open trades:
Equity = Balance + Unrealised P/L
If your balance is $10,000 and you have open trades currently showing -$500 in unrealised losses, your equity is $9,500.
Margin Level The critical metric — expressed as a percentage:
Margin Level = (Equity / Used Margin) × 100%
This is the number your broker watches. When it drops below a certain threshold, bad things happen.
How a Margin Call Actually Works
A margin call isn't your broker calling you on the phone (though it used to be — hence the name). It's an automated warning that your margin level has dropped below the broker's minimum threshold.
Here's a concrete scenario:
Setup:
- Account balance: $5,000
- Leverage: 1:100
- You open 2 standard lots of GBP/USD (position value: ~$200,000)
- Required margin: $2,000
- Free margin at entry: $3,000
- Margin level at entry: 250%
The trade moves against you:
Each pip against you on 2 standard lots costs $20. After 100 pips of drawdown:
- Unrealised loss: -$2,000
- Equity: $3,000
- Margin level: ($3,000 / $2,000) × 100% = 150%
After 175 pips of drawdown:
- Unrealised loss: -$3,500
- Equity: $1,500
- Margin level: 75%
Most brokers trigger a margin call around 80-100% margin level, and will start closing your positions automatically (stop-out) at 50%. At 50% margin level in this example, your equity would be $1,000 — you've lost $4,000 on a $5,000 account.
That's an 80% account loss from a 175-pip move. GBP/USD can move 175 pips in a single day during volatile conditions. This is why position sizing and stop losses aren't optional.
The Margin Level Zones
Think of margin level in three zones:
Green Zone — Above 500% You're well-capitalised relative to your positions. There's room for trades to breathe, and you can open additional positions if good setups appear. This is where you want to operate.
Yellow Zone — 200-500% You're functional but getting stretched. One bad trade or a volatile news event could push you into trouble. Consider whether all your open positions still make sense.
Red Zone — Below 200% You're dangerously close to a margin call. At this level, you have very little cushion for adverse moves. Experienced traders would already be reducing position sizes or closing weaker trades.
Why Traders Get Margin Called
It almost always comes down to three mistakes:
1. Oversizing positions
The most common cause. Traders open positions that are too large relative to their account, leaving insufficient free margin. When pip values are high and margin is thin, even a small adverse move can trigger a call.
Rule of thumb: never use more than 10-15% of your account as margin across all positions combined.
2. No stop losses
Without a stop loss, a losing trade stays open and continues draining equity. The trader hopes it will reverse. Sometimes it does. Often, it doesn't — and by the time they react, the margin level is already in the red zone.
3. Adding to losing positions (averaging down)
A trade goes 50 pips against you, and instead of cutting the loss, you open a second position at the "better" price. Now your required margin has doubled, your equity is already reduced from the first trade's unrealised loss, and you need the market to reverse even more just to break even. This is how small losses become account-ending events.
Practical Margin Management
Know your numbers before entering a trade. Before clicking buy or sell, calculate:
- What margin will this trade require?
- What will my margin level be after opening the position?
- How many pips can the trade move against me before I hit 100% margin level?
Most trading platforms show these numbers in real-time, but you should know them before you enter, not after.
Keep your risk-reward ratio disciplined. If your stop loss is 50 pips, your potential reward should be at least 50 pips — preferably more. This keeps your average loss small relative to your average win, which means your equity stays healthier and your margin level stays higher.
Factor in correlation. If you're long EUR/USD, long GBP/USD, and long AUD/USD simultaneously, you effectively have one very large position: short US dollar. Your margin might look fine for each individual trade, but the total exposure compounds. A strong dollar move hits all three positions at once.
Leave margin for volatility. Spreads widen during news events and low-liquidity periods. Wider spreads temporarily reduce your equity and can push a borderline margin level below the threshold. Budget for this, especially if you hold positions through major economic releases.
Margin Requirements Aren't Fixed
Brokers can and do change margin requirements. Common situations where this happens:
- Before major news events — brokers may increase margin requirements ahead of central bank decisions, NFP releases, or elections
- On exotic pairs — pairs with lower liquidity typically require higher margin than majors
- Over weekends — some brokers increase margin for positions held over the weekend due to gap risk
- During extreme volatility — if markets are in crisis mode, margin requirements may increase with little notice
Always check your broker's margin schedule and be aware that the margin you calculated today might change tomorrow.
A Simple Margin Checklist
Before every trade:
- Calculate the required margin for your intended position size
- Confirm your margin level will stay above 500% after opening the position
- Set a stop loss that limits your potential loss to 1-2% of your account balance
- Check if you have other open positions that are correlated
- Check the economic calendar for upcoming events that could spike volatility
If any of these checks raise a flag, reduce your position size or skip the trade. Preserving capital always matters more than catching a move.
Want to see margin calculations in real-time? Open a demo account with ComoFX and experiment with different position sizes to understand how margin works — with zero risk to your capital.
