Account Setup
Trade Setup
Your Strategy Stats
From your journal or backtest — used to calculate expected value.
Positive edge — strategy is viable
Position Size
How to Use This Calculator
Enter your account balance or choose a preset. This is your total trading capital, not just the margin used for a single trade.
Set your risk percentage. This is the maximum percentage of your account you are willing to lose if this trade hits the stop loss. Most traders use 1–2%.
Enter your entry price, stop loss, and take profit. The calculator determines direction (Long or Short) and your exact position size automatically based on where the stop is relative to entry.
Adjust the win rate slider to match your historical results. This lets you check whether the expected value of your strategy is positive before you commit capital.
How Risk % Affects Your Account Over a Losing Streak
The risk percentage you choose has a compounding effect on your account balance. A single percentage point difference may seem small on one trade but becomes significant across a streak of losses.
| Consecutive Losses | 0.5% Risk | 1% Risk | 2% Risk | 5% Risk |
|---|---|---|---|---|
| 5 losses | −2.5% | −4.9% | −9.6% | −22.6% |
| 10 losses | −4.9% | −9.6% | −18.3% | −40.1% |
| 20 losses | −9.5% | −18.2% | −33.2% | −64.2% |
At 5% risk, 20 consecutive losses wipe out nearly two-thirds of the account. At 1%, the same streak removes less than a fifth — a loss you can realistically trade back from.
Position Sizing Determines Whether You Survive Long Enough to Win
Most traders focus on finding better entries and exits. But position sizing is what keeps you in the game long enough to collect a large sample of trades. A strategy with a real edge only proves itself over hundreds of trades — you have to survive to get there.
With correct sizing, a drawdown is a temporary and expected part of trading. Without it, a short string of losses can end your trading career. Risking too much per trade turns a recoverable situation into an unrecoverable one.
Common Position Sizing Mistakes
Sizing based on conviction rather than a rule. Putting on a larger position because you feel strongly about a setup is not a system — it removes the consistency that makes risk management work.
Using a fixed share count regardless of stop distance. A wide stop with the same number of shares means a much larger dollar loss. Position size must change as the stop distance changes.
Ignoring position value relative to account size. A large position value creates exposure to overnight gaps, margin calls, or forced liquidation even when the percentage stop looks small.
Skipping the expected value check. A correctly sized position is still the wrong trade if your strategy has a negative expected value. Check EV before entering, not just the position size.