Position Sizing 101

Position sizing answers a simple but critical question: How much should I buy or sell right now? Get it right, and you compound wealth. Get it wrong, and you blow your account.

The Core Formula

To calculate your position size, you need three pieces of information:

Account Risk: The dollar amount you are willing to lose (e.g., $100).
Stop Loss: The distance from your entry to your exit if you are wrong (e.g., 50 pips).
Pip Value: How much 1 pip is worth per standard lot for the specific pair you are trading.

Position Size (Lots) = Account Risk ÷ (Stop Loss in Pips × Pip Value)

Fixed Lot vs Dynamic Sizing

Amateurs often trade a fixed lot size (e.g., always trading 0.10 lots). This is dangerous because a trade with a 20-pip stop loss carries vastly different risk than a trade with a 100-pip stop loss.

Professionals use dynamic position sizing. They decide their risk first (e.g., 1%), set their stop loss based on market structure, and then use a calculator to find the exact lot size that bridges the two.

Ready to trade like a pro? Try our free Position Size Calculator now.