Day Trading Simulator

How the Monte Carlo day trading simulator works

A single projection hides how much of a result is luck. This simulator plays your win rate and trade size through 1,000 randomized sequences and reports the spread of where they end, with 30 of them drawn on the chart.

Gains and losses are percentages of the balance at that moment, so results compound. That is why the average sits above the median: a few very lucky runs pull it up, and the median is the better guide to a typical result. The same seed always gives the same runs, so a shared link shows the same numbers.

For each of 1,000 runs and each trade: balance × (1 + gain %) with probability equal to the win rate, otherwise balance × (1 − loss %).

Worked example

Start with $25,000 and 250 trades at a 55% win rate, making 1% on winners and losing 1% on losers. Each trade gains 0.10% on average, so the expected balance is about $32,100, and the median comes in slightly lower because of compounding.

Change the seed to draw new random sequences. The median barely moves, while individual runs on the chart can finish thousands of dollars apart with identical inputs.

What the result does not account for

• Changes in your edge. The win rate stays fixed in every run, and in real trading it is an estimate that drifts.
• Streaks that cluster, because each simulated trade is independent of the last.
• Commissions, slippage and taxes, unless you lower the gain and raise the loss to include them.
• Position limits, since a run can compound into sizes that the market or your broker would not allow.

Frequently asked questions