Position Size Calculator
Calculate exactly how large your next trade should be. Enter your account balance, the percentage you are willing to risk, your entry and your stop loss — the calculator returns your position size in lots, units, or shares.
Results
Fill in the inputs to see your results.
What is position sizing?
Position sizing is the process of deciding how many lots, shares, or coins to buy or sell on a single trade. It is the core of risk management: instead of picking a random trade size, you define in advance how much money you lose if your stop loss is hit, and work backwards from that number.
The formula is simple: position size = (account balance × risk %) ÷ stop distance. A trader with a $10,000 account risking 1% with a 50-pip stop on EUR/USD can trade exactly 0.20 standard lots — no more, no less. The calculator above does this math for you, including currency conversion when your account currency differs from the instrument's quote currency.
How to use this calculator
Select your market — forex, crypto, or stocks — and fill in four numbers. Results update instantly as you type.
- Account balance — your total trading capital.
- Risk per trade — the percentage you accept losing if the stop is hit. 1% is the widely taught standard.
- Entry price — where you plan to open the trade.
- Stop loss price — where your trade idea is proven wrong.
Why position sizing matters more than your entry
Two traders can take the exact same entry and stop loss — one blows up, one survives. The difference is almost always position size. A fixed fractional risk model (risking the same small percentage on every trade) keeps losing streaks survivable: ten consecutive losses at 1% risk still leave you with over 90% of your capital, while the same streak at 10% risk cuts the account by more than half.
Professional risk rules — the 1% rule, fixed fractional sizing, and per-trade risk caps — all reduce to the same calculation this tool performs. Use it before every trade, not after.
Frequently asked questions
What is a position size calculator?
A position size calculator tells you how many lots, shares, or coins to trade so that if your stop loss is hit, you lose exactly the amount of money you decided to risk. It combines your account balance, risk percentage, entry price, and stop loss price into one number.
How much should I risk per trade?
Most risk management frameworks recommend 0.5% to 2% of account equity per trade, with 1% being the common standard. At 1% risk, a streak of 10 consecutive losses — which every strategy eventually produces — costs less than 10% of the account.
Does this calculator work for forex, crypto, and stocks?
Yes. The underlying formula is the same for every market; only the output unit changes (lots for forex, coins for crypto, shares for stocks). For forex, the calculator also converts pip values into your account currency.
Is my data stored or sent anywhere?
No. All calculations run entirely in your browser. Your account balance and trade details never leave your device. Preferences like your last-used currency are stored locally in your browser only.
What is the 1% rule in trading?
The 1% rule means never risking more than 1% of your total account on a single trade. With a $10,000 account, that is $100 of risk per trade. The rule exists to make losing streaks mathematically survivable.