Kelly Criterion Calculator
“How much of my account does the formula put at risk?”
Turn your win rate and payoff into Full, Half, and Quarter Kelly risk fractions, with fees and slippage included.
Open Kelly CalculatorACCOUNT & RISK MANAGEMENT
Trading Risk Management Tools
Plan your risk. Size the trade. Test what happens over hundreds of trades.
- Free
- No sign-up
- Calculated in your browser
Calculators
Position Size Calculator
“How many shares, contracts, or units match my risk budget?”
Start from what you can lose and where your stop is. Get a theoretical quantity, notional exposure, and margin at 1x–10x.
Open Position Size CalculatorTrading Survival Simulator
“What could happen if I repeat the same strategy hundreds of times?”
Run 5,000 simulated accounts to see the spread of ending balances, drawdowns, and how many accounts couldn’t keep trading.
Open SimulatorHow the three tools fit together
- Risk fraction. The Kelly calculator shows how much of the account the formula puts at risk for your win rate and payoff.
- Trade size. The position size calculator turns a risk budget and a stop-loss price into a quantity.
- Repetition. The simulator shows how the account could move when the same kind of trade repeats hundreds of times.
Every tool is educational. The numbers depend entirely on your assumptions, and none of them is a recommendation to buy, sell, or use leverage.