Understanding Position Sizing Beyond Your Account Balance

It's easy to think position sizing is just about how many units you can afford, but it's fundamentally about risk management. The common mistake is sizing based purely on account balance without considering the specific trade's volatility and your defined stop-loss. If you risk, say, 1% of your account per trade, and your stop is 100 pips away, your position size needs to reflect that 100-pip move equaling 1% of your capital, not just how many lots you can open with available margin.

Take $CORN today. It's trading $17.57. If your stop is at $17.495 (the day's low), that's a move of $0.075. To risk $100 on this trade, you'd divide your $100 risk by the $0.075 risk per unit, giving you a position size of approximately 1333 units. This calculation ensures your predefined risk per trade is maintained, regardless of the instrument's price or volatility, a cornerstone of sustainable trading.