Position Sizing Comes Before Prediction
Most beginners obsess over entries. Durable traders decide how much they can lose before they think about how much they might make.
Ask a beginner what they're working on and you'll usually hear about entries: a pattern, an indicator, a signal. Ask someone who has survived a few years and you'll hear about something less glamorous — how much they're willing to lose when the entry is wrong. That inversion isn't cynicism. It's the recognition that you control exposure completely and outcomes not at all.
The only three numbers you fully control
- Entry — the price where you take the position.
- Stop — the price where you accept the idea failed.
- Size — how many units you hold between them.
Multiply the entry-to-stop distance by size and you have your risk — known before the trade, not discovered after it. Fix a risk budget first (a small fraction of the account), and size stops being a guess: size = budget ÷ stop distance. A wider stop simply means a smaller position, not a bigger loss.
Why the math is unforgiving
Losses and gains are asymmetric. A 20% drawdown needs a 25% gain to recover; a 50% drawdown needs 100%. That asymmetry is why professionals defend the downside so aggressively — not because they're timid, but because recovery arithmetic punishes big losses harder than it rewards big wins.
Key takeaway
Decide the loss first. Fix a risk fraction, derive size from the stop distance, and let prediction be the last thing you think about — not the first.
Learn this properly
The free preview module covers these foundations with interactive charts and quizzes.
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