Risk of Ruin Calculator
Estimate the consecutive losses needed to reach a ruin line and an approximate probability from risk %, win rate and trade count.
Results
Fill in the inputs and click Calculate.
- Losses to Ruin Line
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- Window Probability (approx.)
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Risk disclaimer
This model is heavily simplified — it ignores drift, psychological pressure and adding behavior. Not a precise forecast.
What is risk of ruin?
Risk of ruin is the chance that losing streaks shrink the account to an unrecoverable level. The higher the risk per trade, the fewer consecutive losses it takes.
This page uses a simplified model: it finds the losing streak that hits the ruin line and estimates the probability of such a streak within a window.
How to use
- Enter risk per trade as % of account (e.g. 2%).
- Enter win rate (e.g. 50%) and the number of trades in the window.
- Set the ruin line (default 10% remaining) and click Calculate.
Formula
- Streak n = ⌈ln(ruin line) ÷ ln(1 − risk %)⌉
- Approx. probability ≈ trades × (1 − win rate)^n
Example
Risk 2%, win 50%, ruin line 10% → about 114 straight losses hit the line; within 100 trades such a streak is extremely unlikely.
Risk 10% → about 22 straight losses suffice and the approximate probability rises visibly.
FAQ
Is this an exact probability?
No. It assumes fixed fractional risk and independent outcomes; real losing streaks cluster. Treat it as intuition, not prediction.