Position Sizer

Calculates how many shares to buy based on your account size, entry price, and stop loss using three methods: fixed fractional (risk 1% per trade), ATR-based volatility sizing, or Kelly Criterion from your win/loss stats. Takes optional constraints like max position size or sector concentration and tells you which limit is binding. Outputs both JSON and markdown reports with exact shares, dollar risk, and position value. The methodology reference is solid on why you should basically never risk more than 2% per trade and always use half Kelly if you're going that route. No API keys needed, just Python standard library. Good for anyone who wants to stop guessing at position sizes and actually manage risk consistently.

Install to Claude Code

npx -y skills add tradermonty/claude-trading-skills --skill position-sizer --agent claude-code