The math that separates survival from ruin
Imagine you have $10,000 and you risk 10% per trade. After 7 losing trades in a row, your account is at $4,800. To get back to $10k you need to gain 108%. That's the death spiral.
Now imagine you risk 1% per trade. After 7 losses you're at $9,300. To get back to $10k you need 7.5%. Recoverable in days.
This isn't theory — it's compounding math.
The drawdown table every trader should print
| Loss % | Gain needed to recover |
|---|---|
| 10% | 11% |
| 20% | 25% |
| 30% | 43% |
| 50% | 100% |
| 75% | 300% |
| 90% | 900% |
Look at the 50% line. A 50% drawdown requires you to double your money to get back to even. And after a 50% drawdown, your psychology is shot.
How position sizing prevents this
Position size = (Account × Risk %) / (Entry − Stop Loss)
Example: $10k account, 1% risk = $100 risk per trade. If your stop is $50 below entry, you size for 2 contracts/units. If your stop is $200 below entry, you size for 0.5.
This way, every losing trade costs the same — $100 — regardless of how wide the stop is. Risk stays constant; only position size changes.
Why even A+ signals can lose
Trading is probabilistic. Even a 70% win rate means 30% of trades lose. A losing streak of 5 in a row has probability 0.3^5 = 0.24% — which means it WILL happen if you take 1000+ trades.
Position sizing exists for the streak you can't predict.
The 1% rule, bottom line
- 1% = beginner / cautious. 50 losing trades in a row to lose half. Won't ever happen.
- 2% = recommended. 25 losers to lose half. Statistically extreme.
- 5% = aggressive. 14 losers to lose half. Dangerous.
- 10% = gambling. 7 losers to lose half. Will happen.
Pick 1-2% and stick to it. The math protects you when emotions can't.
