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Position sizing: survive first, profit second
Of every trader who blows up, nine out of ten died from position size, not from a bad idea. Sizing is not about maximizing gains — it is about making sure the worst case never takes you out.
- The 1% rule: never risk more than 1% of capital on one trade — ten straight losses cost ~10%
- Size from the stop: risk budget ÷ stop distance tells you how many units to trade
- Volatility-based sizing: trade less when gold is wild, more when it is calm
- Avoid leverage: it amplifies risk, not edge
- Never average down: adding to losers is the classic blow-up script
The math that keeps you alive
The core formula is simple: position size = (account equity × risk per trade) ÷ stop distance. If your account is $10,000, your risk per trade is 1% ($100), and your stop is 200 pips away, you trade a size whose pip value is $0.50 per pip.
The magic is in the compounding of survival: at 1% risk, twenty consecutive losses leave roughly 82% of capital — you can keep playing. At 10% risk, twenty losses leave under 12%, and the account is effectively dead long before that.
The three sizing methods, from simple to smart
- Fixed fraction (the 1% rule): risk a fixed percent of current equity per trade. Simple, robust, and the default choice for most traders.
- Volatility-based: scale size inversely with recent volatility — trade less when markets are wild, more when calm. Keeps risk per move roughly constant.
- Kelly-style (fractional): size by edge divided by variance. Powerful but dangerous at full Kelly; use a fraction (e.g. 1/4) and only after a large, verified sample.
Why blown accounts are almost always a sizing problem
A mediocre strategy with small size survives long enough to let its edge (or its absence) become visible. A good strategy with oversized positions dies on a normal losing streak. The asymmetry is brutal: sizing is the one variable you fully control, and it decides whether you get to keep playing.
This is why EasyQuant's risk gates — daily loss limits, drawdown caps, trade-count limits — apply even in paper trading: the discipline of correct sizing is trained before real money is involved.
Common sizing mistakes
- Sizing from the entry, not the stop: 'I'll risk $200' should mean the stop distance, not the position value.
- Averaging down into losers, which converts a small defined risk into an open-ended one.
- Full-margin leverage that turns a 5% adverse move into a wiped account.
- Increasing size after wins without a verified edge — winners-tilt is as dangerous as revenge trading.
- Ignoring correlated positions: ten 'small' gold trades are one big gold bet.
FAQ
- Is 1% per trade too conservative?
- Not for most traders. At 1%, twenty consecutive losses leave you with roughly 82% of capital — you can keep playing. Scale to 2% only after a stable, verified edge.
- How do stop loss and position size relate?
- Inversely: first pick a stop distance that fits normal noise, then compute size = (capital × risk %) ÷ stop distance. Tighter stop → bigger size; wider stop → smaller size.
- If I go all-in and win, I double up — why not?
- Because the one time you are wrong, you are at zero. Casinos do not fear you winning once; they fear you coming back. Sizing is what keeps you coming back.
- What is volatility-based position sizing?
- Sizing positions inversely to recent market volatility: smaller size when volatility is high, larger when it is low. It keeps the dollar risk per move roughly constant across regimes.
- How does position sizing fit into a backtest?
- Your backtest should apply the same sizing rule you will trade live — fixed fraction, volatility-based, or whatever you chose. If the backtest sizes differently than your live plan, the results do not transfer.
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Not investment advice. Historical results do not guarantee future performance. EasyQuant is a research factory — you execute on accounts you control.