Position Size Calculator
Position sizing decides how many shares or units to trade so that a losing trade only costs a fixed, planned percentage of your account. Enter your account size, risk percentage, entry, and stop-loss to get the exact size.
This position uses 20% of your account capital, while risking only $100 if the stop-loss is hit.
Not sure where your stop belongs? Upload a chart screenshot and Lynx AI reads the structure and the levels that matter, so your stop has a reason behind it.
Try Bullynx freeThe position size formula
Position size = (account size × risk %) ÷ risk per unit
- Risk amount = account size × risk percentage (for example, 1% of $10,000 is $100).
- Risk per unit = the distance from your entry to your stop-loss.
Worked example
With a $10,000 account, risking 1% ($100), an entry at $100, and a stop at $95:
- Risk amount = $10,000 × 1% = $100
- Risk per share = $100 − $95 = $5
- Position size = $100 ÷ $5 = 20 shares
- Position value = 20 × $100 = $2,000
You buy 20 shares. If the stop is hit, you lose $100, exactly 1% of the account, no matter the share price. Pair this with the risk/reward calculator to check the trade is worth taking in the first place.
How to use this calculator
- Enter your account size. The total capital in the account you trade with.
- Set your risk per trade. The percentage of the account you are willing to lose if the stop is hit (often 1 to 2 percent).
- Enter your entry price. The price you plan to enter at.
- Enter your stop-loss. The price where you would exit to cap the loss. The distance to entry sets your risk per unit.
- Read your position size. The tool returns the number of units to trade, the capital at risk, and the total position value.
Frequently asked questions
How do you calculate position size?
Position size = the amount you are willing to risk divided by your risk per unit. Risk amount is your account size times your risk percentage. Risk per unit is the distance between your entry price and your stop-loss. Dividing one by the other gives the number of shares or units to trade.
What percentage of my account should I risk per trade?
Many traders cap risk at 1 to 2 percent of account equity per trade, so that a string of losses does not do lasting damage. The right number depends on your strategy and risk tolerance. The calculator lets you test any percentage to see how it changes your size.
Does this work for stocks and crypto?
Yes. The calculation is the same for any instrument you size by price distance, including stocks, ETFs, and crypto. For forex, where size is measured in lots and pips, use the pip value calculator alongside this one.
Why is my position value larger than my account?
A tight stop-loss produces a large position size, which can exceed your account value and would require margin or leverage. If you do not intend to use leverage, either widen your stop or lower your risk percentage until the position value fits your capital.
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Educational only. Not financial advice. NFA. Bullynx is not a registered investment adviser or broker-dealer. Trading and investing involve significant risk of loss. Read the full risk disclosure.