What is the Risk of Ruin in Trading?
In statistical mathematics and trading, the Risk of Ruin is the probability that you will lose all your trading capital (or reach a drawdown point from which you cannot recover) before achieving success.
Many retail traders mistakenly believe that a strategy with a high win rate guarantees profitability. However, if your risk per trade is too high, or your average losing trade is much larger than your average winning trade, a normal statistical losing streak will inevitably wipe out your account. Our free Risk of Ruin Calculator helps you expose the mathematical flaws in your trading system before you risk real money.
The Holy Trinity of Risk Management
Your mathematical chance of survival depends entirely on the interaction of three core metrics:
Win Rate (%): The percentage of your trades that result in a profit.
Risk-to-Reward Ratio (Payoff Ratio): The size of your average winning trade compared to your average losing trade. (e.g., risking $100 to make $200 gives you a 1:2 ratio).
Risk per Trade (%): The percentage of your total account balance that you risk on a single setup.
Even with a relatively low win rate (like 40%), you can achieve a near 0% Risk of Ruin if your Risk-to-Reward ratio is high enough and your risk per trade is strictly capped at 1%.
How to Use the Risk of Ruin Calculator
To simulate your strategy's survivability, input your historical trading data:
Win Rate: Enter your strategy's historical or expected win percentage.
Average Win / Average Loss: Input your average profit per winning trade and average loss per losing trade to establish your payoff ratio.
Risk Per Trade: Enter the percentage of your equity you risk on each position.
Loss Level (Ruin Point): Define what "ruin" means to you. For some, it's losing 100% of the account. For professionals, hitting a 30% or 50% drawdown is considered the point of ruin.
The calculator will run the statistical probability and output a percentage. Your goal as a trader is to tweak your inputs until your Risk of Ruin is strictly below 1%.
Frequently Asked Questions (FAQ)
Why is my Risk of Ruin 100% even with a 60% win rate? This usually happens because your Risk per Trade is too high. If you risk 10% of your account per trade, you only need 10 consecutive losses to blow the account. Statistically, over a series of 1,000 trades, a 10-trade losing streak is almost guaranteed to happen, even with a 60% win rate.
What is a safe Risk of Ruin percentage? In professional trading and fund management, an acceptable Risk of Ruin is typically 0.5% or lower. If your calculation shows anything above 1%, you should immediately reduce your lot sizes (Risk per Trade) or look for setups with a better Risk-to-Reward ratio.