Free tool
Risk of ruin calculator
Runs in your browser. Nothing you type is sent anywhere or stored.
Your average winner as a multiple of the risk. Losers count as 1R.
Leave blank for no target.
How many trades to look ahead, up to 1,000.
Drawdown floor
Trailing follows your highest closed balance. “Locks” stops it at the starting balance, the common futures rule.
Reach the target
88.2%
Hit the floor
11.8%
Neither yet
0.1%
Within 200 trades. Blue is the target, grey the floor, the rest is still running.
Losses in a row to breach
10
From the starting balance, at $200 a trade.
Break-even win rate
40.0%
At 1.5R winners, before fees. You entered 50%.
Exact for the model, not a forecast. It assumes every trade wins 1.5R or loses 1R at a fixed win rate, independently of the last one. Real trading is streakier than that, and slippage and fees are not in it.
How it works
The calculator treats each trade as a win of your average win in R, or a loss of 1R, at your win rate. It then follows the probability of every balance the account could be at, one trade at a time, removing the paths that touch the floor or reach the target.
Losses in a row to breach = drawdown ÷ risk per trade, rounded up
Because it is exact rather than simulated, it can be checked. With 1R wins and 1R losses on a static floor, the answer must equal the classic gambler’s ruin formula, and it does to nine decimal places. A coin-flip trader (50% at 1R) with the floor 10R below and the target 10R above reaches each first exactly half the time.
What changes the answer most
- Risk per trade. Halving it doubles the number of losses the account can take, which usually moves the result more than any change in win rate you could realistically make.
- The drawdown rule. The same trader breaches a trailing floor more often than a static one, because the floor rises with every new high. A lock at the starting balance removes most of that difference once the account is far enough ahead.
- The edge itself. Below the break-even win rate, more trades only make a breach more likely.
What it leaves out: streaks, changes in size, slippage and fees, and daily loss limits. It describes the arithmetic of your inputs. It is not a forecast, and it is not advice on what to risk.
Questions
What is risk of ruin?
Why does a trailing drawdown raise the risk of ruin?
Is this a Monte Carlo simulation?
Does a good result mean I will pass?
Where do I get my win rate and average win?
Use your real numbers
Traquil measures your actual win rate and average win in R from every trade you log, and tracks your prop account against its rules.
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