Position Size Calculator
Set how much of your portfolio you're willing to risk, and this converts your entry and stop into a share count and dollar position. A risk cap, not a recommendation.
How to read this number
The share count is the largest position that keeps your dollar risk — what you'd lose if the stop is hit — at or below your chosen percentage of the portfolio. It is not a signal to enter the trade. It only answers "if I take this trade with this stop, how many shares keeps my risk in check?"
Formula & assumptions
Common questions
How do you calculate position size?
Decide how much of your portfolio you are willing to risk on the trade, divide that dollar risk by the per-share risk (entry price minus stop price), and the result is how many shares to buy.
What is a good risk percentage per trade?
There is no single right answer. Many risk-conscious traders cap risk per trade well below their total portfolio, but the right number depends on conviction, volatility, and overall portfolio risk.
What is a stop price used for in position sizing?
The stop price defines your per-share risk. The gap between entry and stop, multiplied by shares held, is the dollar amount you are risking if the stop is hit.
Go deeper
Want to see how this position fits the rest of your holdings? Run Portfolio Risk & Fit in AlphaLens.
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