Position Size Calculator
Calculate the correct lot size for any trade based on your account size, risk tolerance, and stop-loss distance. Updates in real time as you type.
How Position Sizing Works
Position sizing determines how many lots (or units) to trade based on how much you're willing to lose if the trade hits your stop-loss. It is the most fundamental risk management technique in trading.
For example, with a $10,000 account risking 1% per trade and a 50-pip stop-loss on EUR/USD, you would trade 0.20 lots (a mini lot). If the trade hits your stop, you lose exactly $100, which is 1% of your account.
Why Position Sizing Matters
Risking a fixed percentage per trade means a losing streak won't wipe your account. Even 10 consecutive losses at 1% risk only costs ~10% of your account.
Without a calculator, traders tend to size up after wins (overconfidence) and size down after losses (fear). A formula removes that bias.
A wider stop-loss automatically reduces your position size. A tighter stop allows a larger position. The risk stays constant regardless of the setup.
As your account grows, your position sizes grow proportionally. As it shrinks during drawdowns, sizes decrease, protecting what remains.
Common Questions
How do you calculate position size in forex?
Divide your dollar risk (account size x risk %) by your stop-loss in pips multiplied by the pip value. For a $10,000 account risking 1% with a 50-pip stop on EUR/USD: ($100) / (50 x $10) = 0.20 lots.
What is a good risk percentage per trade?
Most professional traders risk between 0.5% and 2% per trade. Beginners should start at 0.5% to 1%. Anything above 3% is aggressive and compounds losses quickly during drawdowns.
What is the difference between standard, mini, and micro lots?
A standard lot is 100,000 units (1 pip is roughly $10 on USD pairs). A mini lot is 10,000 units ($1/pip). A micro lot is 1,000 units ($0.10/pip). This calculator shows you which lot type your position falls into.
Should I use the same position size for every trade?
No. Your position size should change based on your stop-loss distance. A trade with a 20-pip stop requires a larger position than one with a 100-pip stop to risk the same dollar amount. That's exactly what this calculator solves.
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