Express Risk Calculator: Size Every Trade Before You Place It
Position sizing kills more accounts than bad strategy selection. The Express Risk Calculator runs the math for you: enter your account size, max loss tolerance, and the strategy's defined risk, and it returns the maximum number of contracts you can responsibly trade.
The default rule: 1–2% of account on any single trade. On a $25,000 account, that's $250–$500 of risk per position. A long call with $300 of premium fits one contract; a vertical spread with $100 max loss fits 2–5 contracts. The calculator translates the rule into an actionable contract count for the structure you're considering.
Where the calculator is most useful: undefined-risk structures. A naked short put on a $200 stock has theoretical max risk of $20,000 per contract. Sizing that by the 1% rule against a $25,000 account means you should trade exactly zero contracts — the calculator will tell you that explicitly, before you fund the trade and discover the math the hard way.
Frequently Asked Questions
Should I use 1% or 2% as my per-trade risk limit?
1% if you're under 100 trades of experience. 2% once you have a documented edge and a journal proving it. Above 2% per trade is degenerate gambling regardless of how confident you feel.
Does the calculator account for commissions and fees?
Yes — most brokers charge $0.65 per contract per side. The calculator subtracts round-trip costs from the position's expected value.