March 28, 2026 · Updated September 26, 2026 · 1 min read
Futures Position Sizing for Automated Traders: A Practical Guide
A step-by-step framework for choosing contract count on automated futures strategies, covering volatility-scaled sizing, risk-per-trade caps, and prop-firm constraints.
Choosing how many contracts to trade is the single most consequential decision in any automated futures system. A great strategy traded too large will blow up; an average strategy traded conservatively will compound. This guide walks through a common framework, step by step. It is general education, not advice on your account: the size you trade is your decision.
Step 1: Define risk-per-trade in dollars
Pick a fixed risk-per-trade, usually 0.5% to 1% of account equity. For a $30,000 account, that's $150–$300 of risk per trade.
Step 2: Convert risk-per-trade to contracts
Divide risk-per-trade by the strategy's typical stop distance in dollars. If your ES strategy uses a 6-point stop, that's $300 per contract. With $300 of risk-per-trade, you trade 1 contract.
Step 3: Volatility-scale
When the market's 14-day ATR doubles, halve your contract count. Volatility regime changes are the #1 cause of unexpected drawdown.
Step 4: Cap with daily-loss limits
Set a daily-loss limit at 3x risk-per-trade. If three trades in a row stop out, the strategy stops for the day. This protects against rare losing streaks AND against software bugs.