Position Size Calculator (Risk Management)
Free online position-size calculator for traders. Enter your account size, the percentage you are willing to risk on one trade, your entry and stop-loss prices, and an optional target, to get the share count, position value and reward-to-risk ratio. It helps cap losses — an educational risk tool, not investment advice. InvestingTradingRuns locally
Use this tool
How to use
- Enter your account equity and the % you will risk on this trade (many disciplined traders keep it at 1–2%).
- Enter the planned entry and stop-loss prices for a long position.
- Add a target price optionally to see the reward-to-risk ratio.
Frequently asked questions
Why size from the stop-loss?
Risk is defined by where you will admit you are wrong (the stop). Sizing so that hitting the stop loses only your chosen % keeps a string of losses from wiping out the account.
What is a good risk per trade?
Common guidance is 1–2% of equity per trade, but the right level depends on your own plan and tolerance.
Does it work for short selling?
This version assumes a long position where the stop is below the entry; reverse the logic for shorts.