Risk of ruin calculator
Estimate the probability of hitting a drawdown limit, using the standard gambler's-ruin model.
Risk of ruin calculator
Probability of ruin
0.03%
Expectancy per unit risked: 0.250
Which model is this, and what does it assume?
This is the classic gambler's-ruin random walk. Your capital is measured in risk units — risking 2% with a 50% ruin threshold gives 25 units. Each trade moves you up by the payoff ratio with probability equal to your win rate, or down by one unit otherwise. The result is the probability that the walk ever reaches zero units.
It assumes every trade is independent, your win rate never changes, your payoff ratio never changes, and you always risk the same fraction. Real trading breaks all four of those assumptions.
This is not a forecast of what will happen to your account. Use it to compare risk settings against each other, not to predict survival.
These calculators work only from the numbers you type in. They do not know your account, your broker or your open positions, and nothing you enter is saved or sent anywhere. They are educational tools, not trading advice.