Last reviewed August 28, 2026

Position Size Calculator: Formula, Scenarios & Interpretation

Calculate a maximum position size from portfolio value, risk percentage, entry price and stop price.

What the calculation measures

Position sizing controls intended loss if the stop/invalidation price is reached under ideal execution.

How to interpret the result

Use a risk percentage that fits your own process; the tool does not recommend a trading strategy.

Run scenarios instead of one answer

Change the most uncertain input and compare outcomes. A calculator is most useful when it shows sensitivity, not when one estimate is treated as a guarantee.

Limits and assumptions

Gaps, slippage, leverage and correlated positions can cause actual portfolio risk to differ.

Try the browser tool

Work with your file locally.

Open Position Size Calculator