Position Size Calculator
Size every trade by a fixed slice of your account so one loss can't sink you. Enter your account, the risk you'll take per trade, your entry and your stop — and get the exact number of shares.
- Free, no signup
- Calculated in your browser, not on our servers
- Formula shown with your numbers
Your trade
Position size
$100.00 ÷ |50.00 − 48.00| = 50.0 → 50 shares
Shares round down so you never exceed the budget. Gaps can fill past a stop, so a real loss can be larger.
Same trade at other risk levels
| Risk | Dollars | Shares | Position | % of account |
|---|---|---|---|---|
| 0.25% | $25 | 12 | $600 | 6.0% |
| 0.5% | $50 | 25 | $1,250 | 12.5% |
| 1% | $100 | 50 | $2,500 | 25.0% |
| 1.5% | $150 | 75 | $3,750 | 37.5% |
| 2% | $200 | 100 | $5,000 | 50.0% |
For education and planning. Results are estimates that leave out taxes and may leave out fees and slippage. Not investment advice. Check the numbers against your broker before you trade.
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<p style="font-size:13px">Position Size Calculator by <a href="https://stocksetups.com/tools/position-size-calculator">StockSetups</a></p>How it works
Professional sizing flips the usual question. Instead of "how many shares can I afford?", you ask "how many shares keep my loss to X% of my account if the stop hits?" The formula is simple: shares = (account × risk %) ÷ (entry − stop). The distance to your stop sets the size, not your account balance.
That's why a tighter stop lets you take more shares for the same dollar risk, and a wide stop forces fewer. It also keeps your risk constant across very different stocks — a $200 risk on a $5 stock and a $400 one behave the same in your P&L. Most swing and position traders risk 0.5–2% per trade; smaller is steadier.
On StockSetups, every setup already ships with an entry, stop and target, so you can drop those numbers straight into this calculator (or read the position size off the trade plan).
Frequently asked
How do you calculate position size?
Position size = (account size × risk per trade %) ÷ (entry price − stop price). The result is the number of shares that caps your loss at your chosen risk if the stop is hit. Round down so you never exceed the risk.
What percent should I risk per trade?
Most traders risk between 0.5% and 2% of their account per trade. Lower risk smooths your equity curve and survives losing streaks; higher risk grows (and drains) the account faster.
Can I use this for forex or crypto?
It sizes in whole shares, so it's built for stocks and ETFs. The risk formula is the same for any market, but forex is sized in lots with a pip value and crypto in fractional units, so this result won't convert directly.
How do I size a position using ATR?
Use a multiple of ATR as the stop distance. With an ATR of $1.25 and a 2× stop, the stop sits $2.50 from entry, so a $100 risk budget buys 40 shares. Volatile stocks get wider stops and fewer shares.
Does a wider stop mean a bigger or smaller position?
Smaller. For the same dollar risk, a wider stop (bigger entry-to-stop distance) means fewer shares, and a tighter stop means more shares.
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