Position Size Calculator
Calculate trade size from account risk and stop-loss distance. Free position size calculator showing shares to buy and money at risk.
About the Position Size Calculator
Position sizing is the core of risk management: it decides how many shares or units to buy so that if your stop-loss is hit, you lose only a set percentage of your account. This free position size calculator takes your account balance, the percentage you are willing to risk, your entry price and your stop-loss, and returns the exact position size.
The method is: risk amount = account × risk %, then position size = risk amount ÷ (entry − stop). Risking 1% of a 500,000 account with a 5-per-share stop distance means you risk 5,000, so you buy 1,000 shares. This keeps every loss small and consistent regardless of the trade.
Traders and investors use position sizing to survive losing streaks and avoid ruin from a single bad trade. This is an educational tool, not financial advice — trading carries a real risk of loss. Everything runs in your browser.
How to Use the Position Size Calculator
- 1Enter your total account balance.
- 2Enter the percentage of the account you are willing to risk on this trade.
- 3Enter your planned entry price and your stop-loss price.
- 4Read the position size and the money you are risking.
Frequently Asked Questions
How do I calculate position size?
First find the money at risk: account balance × risk percent. Then divide by the per-unit stop distance (entry minus stop). Risking 1% of 500,000 gives 5,000; with a stop 5 below entry, you buy 5,000 ÷ 5 = 1,000 shares.
How much of my account should I risk per trade?
Many traders follow the 1-2% rule: risk no more than 1-2% of the account on any single trade. At 1%, it would take a long string of losses to seriously dent your capital, which keeps you in the game to recover.
Why does stop-loss distance matter for position size?
A tighter stop lets you buy more shares for the same money at risk, and a wider stop forces a smaller position. This is why position size and stop placement must be decided together — the stop defines your risk per share.
Does this work for forex and crypto too?
Yes. The logic is identical: risk amount divided by the distance from entry to stop, measured in the instrument's price units. For forex you may need to convert the stop distance into money using pip value first.