Position Size Calculator
The fastest way to answer the only question that matters before you click buy: how many shares can I take without risking too much? Enter your account size, the percent you are willing to risk, your entry and your stop-loss. You instantly get the exact share count, position value, worst-case loss, and your 1R, 2R and 3R profit targets. Free, no sign-up.
Calculations are estimates and exclude commissions, slippage and fees. This is an educational tool, not investment advice.
Now you can size any trade. Get free real-time alerts the moment a stock moves on unusual volume, no card required.
No card · 5 premium daysWhy position sizing matters more than picking winners
Most traders blow up not because they are wrong too often, but because a single oversized trade wipes out weeks of gains. Fixed-percentage position sizing flips that. By risking the same small slice of your account every time, no one loss can seriously hurt you, and you stay in the game long enough for your edge to play out. The math is simple, but doing it by hand under pressure is where mistakes happen, so this tool does it for you the instant a setup appears.
The formula: shares = (account size × risk %) ÷ (entry − stop). The top is the dollars you are willing to lose; the bottom is what you lose per share if the stop is hit. Everything else, position value, percent of account, and R-multiple targets, follows from those four inputs.
Frequently asked questions
Everything you need to know about position sizing and risk per trade on TheDesperateTrader.
- How do I calculate position size?
- Position size is the amount you risk per trade divided by your risk per share. First, decide how much of your account to risk on the trade (for example 1% of a 10,000 dollar account is 100 dollars). Then take the difference between your entry price and your stop-loss price, which is your risk per share. Divide the dollar risk by the risk per share to get the number of shares. This calculator does it instantly as you type.
- How much of my account should I risk per trade?
- A common rule among day traders is to risk between 0.5% and 2% of your account on any single trade. Risking a small, fixed percentage means no one loss can seriously damage your account, and you can survive a losing streak. Smaller percentages are more conservative; the right number depends on your strategy and risk tolerance.
- What is the position size formula?
- Shares to buy = (Account size times Risk percentage) divided by (Entry price minus Stop-loss price). The top of the fraction is the dollars you are willing to lose; the bottom is how much you lose per share if the stop is hit. The result is the largest position that keeps your loss at or below your chosen risk.
- What is 1R, 2R and 3R?
- R is your risk on the trade, the distance from your entry to your stop. A 1R target is a price that would gain the same amount you were risking, 2R is twice that, and so on. Framing targets in R makes it easy to judge reward versus risk: a setup that only offers 1R for the risk taken is usually worse than one offering 2R or 3R.
- Does this work for short trades?
- Yes. Put your entry price and a stop-loss above it (where you would cover if wrong). The calculator uses the distance between entry and stop for risk per share either way, and it points the profit targets in the short direction automatically.
- How do I find trades to size in the first place?
- Our free real-time scanner flags stocks the moment they trade on unusual volume, across the whole U.S. market with no 15-minute delay. Once a name is moving, use this calculator to size the trade to your risk, then manage it from the live chart. No credit card required.
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