Position Sizing
Risk Management
Position sizing is the process of choosing how large a trade to place so that a loss stays within a planned percentage of the account.
What is position sizing?
Position sizing is the calculation that decides how many units, lots, or contracts of an instrument to trade so that, if the stop-loss is hit, the resulting loss matches the amount of capital the trader planned to risk — no more. It connects three numbers: account size, the chosen risk per trade, and the distance in pips (or price) to the stop-loss.
Rather than trading a fixed lot size on every trade regardless of the setup, position sizing adjusts the trade size to fit the risk of that specific trade.
A worked example
Take a $10,000 account where the trader risks 1% per trade, or $100. If the stop-loss on a EUR/USD trade sits 25 pips away from entry, and each pip on a standard lot is worth roughly $10, the trader works backwards: $100 risk ÷ (25 pips × $10/pip per standard lot) = 0.4 lots. Trading 0.4 lots with a 25-pip stop keeps the loss close to $100 if the trade goes wrong.
If the next setup has a tighter 10-pip stop, the same $100 risk allows a larger position — around 1 lot — because each pip of adverse movement represents less of the total risk budget. This is why position size should flex with stop distance, not stay fixed.
Why it matters
Without position sizing, two trades with identical dollar stop-losses can carry wildly different risk simply because their price distances differ. Getting position sizing right is what keeps risk per trade consistent from trade to trade, which in turn is central to any risk management plan — most brokers’ trading platforms include a built-in position-size or lot calculator to automate this math.
Quick recap
- Position sizing sets trade size based on account risk and stop-loss distance, not habit.
- Formula: position size = (account risk in money) ÷ (stop distance in pips × pip value).
- A wider stop calls for a smaller position; a tighter stop allows a larger one, for the same dollar risk.
- It keeps risk per trade consistent, which is foundational to disciplined risk management.
Trading forex and CFDs carries a high level of risk and may not be suitable for all investors. Past performance is not indicative of future results.