Risk of Ruin Calculator
Calculate the exact probability that your trading account hits a critical drawdown or goes to zero, based on your win rate, reward-to-risk ratio, and risk per trade. Find out before you trade whether your edge is enough to survive variance.
Results
What If You Risked More? (Sensitivity Analysis)
| Risk per Trade | Risk of Drawdown | Risk of Ruin | Expected Growth | Verdict |
|---|
What is risk of ruin in trading?
Risk of ruin is the statistical probability that a trader loses enough capital to stop trading, either by hitting a predefined critical drawdown or by reducing the account to zero. It is expressed as a percentage: a 5% risk of ruin means there is a 5% chance the account is wiped out over a long series of trades, given your current strategy.
Risk of ruin combines three variables: your win rate, your reward-to-risk ratio, and the percentage of your account you risk per trade. A profitable strategy can still carry a high risk of ruin if position sizes are too large, because variance (a normal run of losses) drains the account before the edge can play out. The Forex Complex risk of ruin calculator runs the numbers so you know your survival odds before you commit real money.
Why risk of ruin matters more than win rate
A high win rate does not protect your account. Risk of ruin matters more than win rate because it accounts for variance and position sizing, the two things that actually blow up accounts.
A trader with a 70% win rate who risks 10% per trade has a meaningfully higher risk of ruin than a trader with a 50% win rate who risks 1%. Variance produces losing streaks even with a strong edge: at a 60% win rate, a run of 7 consecutive losses happens roughly once every 1,200 trades, which is a normal Tuesday over a trading career. If each of those 7 losses costs 10% of the account, the account is down over 50% before the edge recovers.
How does the risk of ruin calculator work?
The Forex Complex risk of ruin calculator takes your win rate, reward-to-risk ratio, and risk per trade, and returns the probability that your account hits ruin over a long series of trades. The simplified analytical formula for a fixed-fractional strategy is:
Risk of Ruin = ((1 − Edge) ÷ (1 + Edge)) ^ (Capital ÷ Risk per trade)
Where Edge is your expected value per trade as a fraction of the amount risked. For a strategy with a 50% win rate and a 2:1 reward-to-risk ratio, the edge is positive (you win £2 for every £1 risked, half the time), so the risk of ruin falls as you reduce risk per trade.
The analytical formula assumes a fixed bet size and a binary win/loss. Because real trading has variable outcomes, partial wins, and changing position sizes, the calculator uses a Monte Carlo simulation (running thousands of randomized trade sequences) to produce a more realistic probability than the closed-form equation alone.
How to calculate risk of ruin
Use The Forex Complex calculator in four steps:
- Enter your win rate. The percentage of trades you win. Use your real, backtested or journaled win rate, not an optimistic estimate. If you do not have one, the consistency calculator can help you assess your historical results.
- Enter your reward-to-risk ratio. How much you win on a winning trade versus how much you lose on a losing trade. A 2:1 ratio means winners are twice the size of losers.
- Set your risk per trade. The percentage of your account you risk on each trade. The professional standard is 1% to 2%.
- Set your ruin threshold. The drawdown level you define as “ruin” (often 100% for full account loss, or a lower figure like 50% that ends your trading in practice).
The calculator returns your probability of ruin as a percentage. Use the position size calculator to translate your chosen risk per trade into exact lot sizes.
Risk of ruin trading example
A trader has a 50% win rate, a 2:1 reward-to-risk ratio, and risks 2% per trade. Running this through the calculator produces a risk of ruin close to 0% over a typical account life, because the positive edge combined with small position sizing makes total account loss statistically negligible.
Now change one variable: the same 50% win rate and 2:1 ratio, but risking 10% per trade. The risk of ruin jumps dramatically, because a normal losing streak now carries enough weight to drain the account faster than the edge can compound. Same edge, same win rate, vastly different survival odds. Position sizing is the lever.
Turn Trading Calculations Into Real Trading Decisions
Use your calculated risk levels, position sizing, and technical analysis together with live forex trading signals and market commentary from The Forex Complex.
Risk of ruin reference table (win rate vs risk per trade)
This table shows the approximate long-run risk of ruin (probability of total account loss) for a strategy with a 1:1 reward-to-risk ratio at different win rates and risk-per-trade levels. Higher reward-to-risk ratios reduce these numbers significantly.
| Win rate | Risk 1% per trade | Risk 2% per trade | Risk 5% per trade | Risk 10% per trade |
|---|---|---|---|---|
| 40% | ~100% (certain ruin) | ~100% | ~100% | ~100% |
| 45% | ~100% | ~100% | ~99% | ~87% |
| 50% | High (break-even, no edge) | High | High | High |
| 55% | ~0% | ~0% | ~1.5% | ~13% |
| 60% | ~0% | ~0% | ~0% | ~1.7% |
| 65% | ~0% | ~0% | ~0% | ~0.2% |
The pattern is clear: below a 50% win rate at 1:1, ruin is near-certain over time regardless of position sizing. Above 50%, smaller position sizes drop the risk of ruin to effectively zero. This is why professional traders obsess over risk per trade, not just win rate.
What affects risk of ruin in forex trading?
Three inputs determine your risk of ruin. Change any one and the probability shifts.
- Win rate. The percentage of trades that close in profit. A higher win rate lowers risk of ruin, but only in combination with the other two factors. Win rate alone is not enough.
- Reward-to-risk ratio. How large your winners are relative to your losers. A trader with a 40% win rate and a 3:1 ratio is profitable and can have a low risk of ruin, because the large winners outweigh the frequent small losses.
- Risk per trade (position sizing). The single most powerful lever. Doubling your risk per trade does not double your risk of ruin, it increases it exponentially, because larger positions let normal losing streaks do permanent damage.
The interaction between these three is what the calculator models. A change that looks small (moving from 2% to 4% risk per trade) can move risk of ruin from negligible to dangerous.
Monte Carlo simulation in trading explained
A Monte Carlo simulation in trading runs thousands of randomized sequences of your trades to map the full range of outcomes you could realistically experience, not just the average. Instead of assuming your trades happen in a neat order, it shuffles them thousands of times to reveal the worst drawdowns and best runs hidden inside your edge.
This matters because two traders with identical win rates and reward-to-risk ratios can have very different experiences depending on the order their wins and losses arrive. A losing streak early in an account’s life is far more dangerous than the same streak later, after the account has grown a buffer. Monte Carlo captures this sequence risk that a single backtest cannot.
Monte Carlo vs the analytical formula
The analytical risk of ruin formula gives a single closed-form number assuming fixed bet sizes and binary outcomes. A Monte Carlo simulation gives a distribution of outcomes by running the strategy thousands of times with randomized trade order. For real forex trading, where position sizes and outcomes vary, Monte Carlo is more realistic, which is why The Forex Complex calculator uses it. The analytical formula is useful as a quick sanity check; Monte Carlo is the tool for actual risk planning.
How to reduce your risk of ruin in trading
Risk of ruin drops fastest when you cut your risk per trade. Five actions that lower it:
- Risk 1% to 2% per trade, never more. This is the single most effective change. Moving from 5% to 1% risk per trade can turn a meaningful risk of ruin into a negligible one with no change to your strategy.
- Improve your reward-to-risk ratio. Targeting 2:1 or 3:1 trades means you can be profitable with a sub-50% win rate and still carry a low risk of ruin.
- Avoid correlated positions. Three EUR trades open at once is effectively one large position. Correlated exposure multiplies your real risk per “trade” beyond what the calculator shows for a single position.
- Reduce size during drawdowns. Cutting position size when your account is down preserves capital and lengthens the runway for your edge to recover. The drawdown calculator shows how deep a hole each risk level digs.
- Verify your real win rate. Risk of ruin calculations are only as good as the inputs. An inflated win rate produces a falsely comfortable number. Use journaled, real results.
Common mistakes traders make with risk management
Five mistakes that quietly raise risk of ruin:
- Overestimating win rate. Traders remember wins and forget losses. A journaled 48% win rate often feels like 60%. Feeding an optimistic win rate into any calculator produces a dangerously low risk of ruin figure.
- Risking too much per trade. Risking 5% or 10% per trade feels fine during a winning run and catastrophic during the inevitable losing streak. Position sizing is the lever that turns a good strategy into a blown account.
- Ignoring sequence risk. The order of wins and losses matters. An early losing streak can end an account that would have been profitable if the same trades arrived in a different order. Monte Carlo modelling exposes this; a single backtest hides it.
- Treating a positive expectancy as safety. A profitable strategy can still blow up if position sizes are too large relative to variance. Positive edge is necessary but not sufficient for survival.
- Never recalculating. Win rate and reward-to-risk drift over time as markets change. A risk of ruin figure from a year ago may no longer reflect your current edge. Recalculate periodically.
Frequently asked questions
How accurate is a risk of ruin calculator?
A risk of ruin calculator is only as accurate as the inputs you give it. The maths is sound, but if your win rate or reward-to-risk ratio is optimistic rather than journaled, the output will understate your true risk. A Monte Carlo-based calculator like The Forex Complex tool is more realistic than the simple analytical formula because it accounts for the random order of wins and losses, which is where real accounts fail.
What is a good risk per trade in forex trading?
A good risk per trade is 1% to 2% of your account balance, the professional standard followed by most disciplined traders. Risking 1% means a 20-trade losing streak costs roughly 18% of the account, which is survivable. Risking 5% or more turns a normal losing streak into account-ending damage. New traders should start at 0.5% to 1% until they have a journaled, consistent edge.
How can traders reduce their risk of ruin?
The fastest way to reduce risk of ruin is to lower the percentage risked per trade, since position sizing affects ruin exponentially. Moving from 5% to 1% risk per trade can turn a meaningful risk of ruin into a negligible one with no change to the underlying strategy. Improving the reward-to-risk ratio, avoiding correlated positions, and cutting size during drawdowns all reduce it further.
What is a good risk of ruin?
A good risk of ruin is below 1%, and ideally close to 0% over the realistic life of your account. A risk of ruin above 5% means there is a real, material chance you lose your account purely to variance, even with a positive edge. Professional risk managers target a risk of ruin so low it is effectively zero, achieved through small position sizes and a verified edge.
What is the 2% rule in forex?
The 2% rule states that you should never risk more than 2% of your trading account on a single trade. It is a position-sizing guideline designed to keep risk of ruin low by ensuring no single trade, and no normal losing streak, can do catastrophic damage. At 2% risk per trade, a trader can survive a long run of losses and still have capital to recover, which is the core purpose of risk management.
Twitter