Risk of Ruin Table: Probability of a 50% Drawdown by Win Rate and Risk
Each faint trail is one simulated future for this strategy. The bold line is the median — half of runs finished above it, half below. The shaded band spans the lucky 10th to unlucky 90th percentile, so an outcome inside the band was reasonable to expect; outside, less so.
- This table shows the simulated chance of a 50% drawdown within 1,000 trades
- A coin-flip 1:1 strategy has a 37% chance of halving the account at 2% risk
- A 45% / 1.5R strategy goes from under 1% ruin at 2% risk to 19% at 5% risk
- Edge and risk interact: weak edges become dangerous at much lower risk levels
- For your exact inputs, use the Risk of Ruin calculator
Risk of ruin formulas are useful, but most traders want a quick answer: given roughly my win rate and my position size, how likely am I to blow up half the account? This page is that reference table.
Method
Each cell is the share of 6,000 simulated trading paths that hit a 50% drawdown within 1,000 trades. Risk is a fixed percentage of the current balance (compounding). No trading costs were included — real results will be slightly worse.
The table
| Win rate · R:R | Expectancy | 1% risk | 2% risk | 3% risk | 5% risk |
|---|---|---|---|---|---|
| 40% · 1.5R | 0.00R | 9.8% | 49.3% | 72.5% | 90.6% |
| 50% · 1.0R | 0.00R | 3.9% | 36.8% | 61.4% | 84.6% |
| 45% · 1.5R | +0.13R | 0.0% | 0.7% | 4.4% | 18.9% |
| 50% · 1.5R | +0.25R | 0.0% | 0.0% | 0.1% | 2.1% |
| 45% · 2.0R | +0.35R | 0.0% | 0.0% | 0.1% | 1.6% |
| 55% · 1.5R | +0.38R | 0.0% | 0.0% | 0.0% | 0.2% |
How to read the table
The top two rows are zero-expectancy strategies — one where you win exactly as much as you need to break even. They show what happens to a trader with no edge who simply sizes up. At 1% risk the 40% / 1.5R strategy still ruins in about 1 in 10 simulated runs. At 2% risk it ruins in nearly half.
The bottom four rows all have a positive expectancy. Even a modest edge like 45% / 1.5R (+0.13R per trade) is nearly ruin-proof at 1–2% risk. But push to 5% risk and the same edge carries an almost 1-in-5 chance of halving the account before 1,000 trades.
The patterns that matter
- Zero-expectancy strategies are not safe at any risk level — they just fail more slowly at 1%
- Positive expectancy collapses ruin risk dramatically at 1–2% risk, but the protection erodes fast above 3%
- The difference between 2% and 5% risk is larger than the difference between a weak edge and a strong one
- Compounding amplifies both gains and losses — the table assumes compounded risk, not fixed-dollar risk
How to use this table
Find the row closest to your strategy’s win rate and reward:risk. Then scan across to your current risk per trade. If the cell shows more than 5%, your sizing deserves a second look. If it shows more than 20%, your account is carrying more risk than most traders would consciously accept.
The table uses round numbers. Your actual win rate and R:R are not round numbers, and your results will sit somewhere between rows. Use the calculator below to run your exact inputs.