Define risk as a percentage, not a dollar amount
Risking a fixed percentage of account equity per trade — commonly 0.5% to 2% — rather than a fixed dollar amount keeps risk proportional to account size as it grows or shrinks. This prevents a string of losses from an early, larger account balance turning into an outsized risk on a now-smaller one.
It also removes a layer of decision-making under pressure: once the percentage is fixed, position size becomes a calculation rather than a judgment call made trade by trade.
Let stop-loss distance determine lot size
Rather than picking a lot size first and then figuring out where to place a stop, work backward: decide your stop-loss level based on where the trade idea is invalidated, then calculate the lot size that keeps your risk within your chosen percentage.
This ordering matters because it keeps the stop-loss tied to the market structure of the trade, rather than to an arbitrary dollar amount that happens to fit a preferred position size.
A simple formula
Account risk in dollars ÷ stop-loss distance in pips ÷ pip value per lot gives you the appropriate lot size. Working through this calculation before every trade removes guesswork from the equation entirely.
Account for correlated positions
Two trades on different but correlated pairs — such as EUR/USD and GBP/USD — can behave like a single larger position if both move against you at the same time. Sizing each trade independently without accounting for correlation can understate real portfolio risk.
A simple safeguard is to treat clearly correlated positions as a combined risk allocation rather than two fully independent ones, reducing individual size accordingly.
Position sizing is the one variable in trading you have complete control over — unlike market direction, it doesn't depend on being right.
Frequently asked questions
What percentage of my account should I risk per trade?
Most experienced traders risk between 0.5% and 2% of account equity per trade, with more conservative sizing generally preferred by newer traders or those trading less-tested strategies.
Does position sizing matter less if my win rate is high?
No — even high win-rate strategies can face a losing streak, and inconsistent position sizing means a single oversized loss can undo the gains from many smaller winning trades.
Pips School Editorial
The Pips School editorial team writes independent educational material on forex markets, broker selection and risk management.
Editorial principles
