Free Monte Carlo Simulator for Trading
Enter your win rate, average win and average loss, and the simulator plays your plan out up to 5,000 times. See how often the account falls to your ruin level, how deep drawdowns get, and how wide the range of outcomes is. Online, no login, no download.
Simulator
Define your trading plan and risk parameters.
Results
Risk metrics from your simulations.
- Median Final Balance
- P10 Balance
- P90 Balance
- Ruin Probability
- Avg Max Drawdown
- Expectancy
Final Balance Distribution
This chart shows how frequently each final balance range appears across all simulations.
Email me these results
We’ll send the numbers to your inbox. No account required.
If the address is valid, your results are on the way.
How This Monte Carlo Simulation Works
- Each simulated trade is a win with a probability equal to your win rate, independent of the trades before it.
- A win adds your average win and a loss subtracts your average loss. Any value entered as an R-multiple is multiplied by your risk per trade, so a 2R win at $100 risk adds $200. Risk stays the same dollar amount on every trade; nothing compounds.
- A run stops early if the balance falls to your ruin level: the starting balance minus the ruin threshold. With $10,000 and a 20% threshold, that level is $8,000.
- This repeats for the number of trades you set (up to 500), across the number of simulations you set (100 to 5,000). The results summarise every run.
New to R? R-multiples explained covers how to measure a trade by its risk instead of its dollars. The free position size calculator turns 1R into a lot size.
How to Read the Results
- Median final balance
- Half the runs ended above it and half below.
- P10 and P90 balance
- 10% of runs ended below P10 and 10% ended above P90. The gap between them is how much luck your plan carries.
- Ruin probability
- The share of runs that touched your ruin level. Risk of ruin in trading explains why this number matters more than the median.
- Avg max drawdown
- Each run's deepest fall from its own peak, averaged across all runs.
- Expectancy
- The average dollar result per trade: win rate × average win − loss rate × average loss. With the default inputs (60% win rate, 2R win, 1R loss, $100 risk): 0.60 × $200 − 0.40 × $100 = $120 − $40 = $80 per trade, or +0.8R. Win rate vs risk reward ratio shows how the two trade off.
What This Simulation Does Not Tell You
- Whether your win rate is real. It takes the number you type as exact. A win rate from a few dozen trades has a wide margin of error, and how many trades before you know a strategy works shows how wide.
- How real trades vary. Every win is the same size and every loss is the same size. Real results spread out, and slippage or a gap can make one loss bigger than planned.
- Streaks you cause. Each simulated trade is independent. Tilt, a strategy that stops working or a change in the market makes real losses cluster. How long a losing streak is normal shows what chance alone produces.
- Costs. Fees, spreads and swaps are not included unless they are already in your average win and loss.
Common Risk Mistakes
- Entering a backtest win rate as if it were a live one.
- Reading the median as the forecast. One run in ten ends below P10, so plan for that result too.
- Setting the ruin threshold to 0%, which counts any dip to or below the starting balance as ruin. Use the drawdown at which you would actually stop trading the plan.
- Running 100 simulations and trusting the tails. More runs steady the P10 and ruin numbers, but they never make your inputs more accurate.
- Judging the plan from one equity curve. How to read an equity curve covers what a single path hides.
FAQ
What is a Monte Carlo simulation in trading?
It plays a trading plan out many times with random luck, using your win rate and your average win and loss, so you see the range of results the same edge can produce instead of a single average. A backtest is one sequence of trades; a Monte Carlo simulation shows thousands.
Is this Monte Carlo simulator free?
Yes. It runs online with no login and no download. Emailing yourself the results is optional.
How is probability of ruin calculated here?
It is the share of simulations in which the balance fell to your ruin level, which is the starting balance minus your ruin threshold. With a $10,000 balance and a 20% threshold, a run counts as ruined the moment it touches $8,000, and that run stops there.
How many simulations should I run?
The tool accepts 100 to 5,000. Use 1,000 or more when you care about the tails, the P10 balance and the ruin probability, because 100 runs leave those numbers noisy. More runs do not make your win rate or R values any more accurate.
What should I enter for win rate and average win and loss?
Your own numbers from logged trades, in R-multiples if you have them, taken only from trades that follow the plan you are testing. A small sample makes the win rate itself uncertain, and the simulator treats whatever you type as exact.
Why do the same inputs give the same result every time?
The simulation is seeded from your inputs, so identical inputs return identical numbers and a shared link shows the same result to everyone. Changing any input, including the number of simulations, draws a new set of sequences.
Does the simulator compound returns?
No. Every trade risks the same dollar amount, set by your risk per trade or by your fixed win and loss amounts. If you size as a percentage of your current balance, your real range of outcomes will differ.