Analytical is the upper bound
The closed-form formula assumes symmetric bets and unbounded trade count. When it returns 1 % RoR, your real-world risk over a finite horizon is usually lower. When it returns > 5 %, you are absolutely in trouble.
Free trader tools
Risk of Ruin Calculator
Punch in your starting balance, win rate, average R and a horizon of trades. We run two calculations side by side: the closed-form risk of ruin (when bets are symmetric) and a 1000-trial Monte Carlo simulation in a web worker — so you see the realistic distribution, not just the headline.
Most retail traders have a higher risk of ruin than they realise — and the math is unforgiving. If RoR is over 5 %, your sizing is wrong, your win rate is wrong, or both.
MindTrajour_RiskOfRuin
How to read these two numbers together
Three reads to take seriously before you decide your sizing is fine.
Monte Carlo is the realistic lens
Asymmetric R, finite horizons, ruin thresholds — the simulation models all three. Compare the two channels: when they disagree, the simulation is closer to the real account.
Distribution beats average
The median final balance can look healthy while the bottom-10 % balance is a wipeout. Look at the spread, not just the centre — that gap is the variance you have to live through.
RoR is a sizing problem
If your risk of ruin is over 5 %, your sizing is wrong, your win rate is wrong, or both.
MindTrajour shows your real win rate and average R per strategy — so you can fix the input that is actually broken instead of guessing.
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Keep stacking your edge
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Punch in your four strikes, the net credit, and the number of contracts. We give you back the max profit, max loss, both break-evens, and a payoff diagram that shows exactly where the trade lives or dies.
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Everything you need to know before sizing your next trade.