How many lots can I trade with my account size?

Multiply your account size by your target leverage usage percentage to get your margin budget, multiply that by your broker leverage to get your maximum notional size, then divide by 100,000 (and by the exchange rate, for a pair not quoted in USD) to get your maximum lot size.

Why use a target usage percentage instead of my broker's actual margin requirement?

A broker's minimum margin requirement is set to avoid a margin call, not to keep your position size responsible. Using a smaller personal target, commonly 5 to 15 percent of the account for one position, leaves room for the trade to move against you before you're anywhere near your broker's own limit.

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Forex Trading Tools

Given my account size, what's the largest forex lot size I can responsibly trade?

The market doesn't reward being right. It rewards managing being wrong, cheaply.

Jason Parker, Founder of Trading Habits

Enter Your Account And Leverage Target

This is the mirror question to the Minimum Account Size Calculator: instead of solving for the account you'd need for a given lot size, this solves for the lot size your existing account can responsibly carry.

Your Result

Fill in your account size, leverage, and target usage on the left, then click Calculate.

How this is calculated

Margin budget equals your account size times your target usage percentage. This is the dollar amount of margin you're willing to commit to this one position, not the broker's bare minimum.
Maximum notional size equals that margin budget times your broker leverage.
Maximum lot size equals that notional size divided by 100,000 (one standard lot's unit size), divided again by the exchange rate for a pair not already quoted in USD.
This tells you the largest position your own target usage allows, not the largest your broker will let you open. A broker's actual margin requirement is usually far looser than a responsible personal target.

Risk & liability disclaimer: This calculator performs simple arithmetic on the numbers you enter and does not pull live exchange rates or your actual broker's margin schedule. Actual margin requirements vary by broker, account type, and currency pair. This is not financial advice. Trading Habits is not a broker-dealer, registered investment adviser, or tax professional, and is not affiliated with any broker, exchange, or data provider. Forex trading involves substantial risk of loss, and leveraged trading can amplify losses beyond your initial margin in some account types.

Given my account size, what's the largest forex lot size I can responsibly trade?

Enter Your Account And Leverage Target

Your Result

How this is calculated

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