What is a position size calculator?
A position size calculator tells you exactly how many lots to trade so a losing trade only costs a fixed, pre-decided amount of your account. You decide how much to risk (say 1% of your balance), enter your stop-loss distance in pips, and it returns the precise lot size. It's the single most important risk-management tool in trading — getting it right is what stops a run of losses from wiping out your account.
How to calculate position size in forex
Worked example: A $10,000 account risking 1% ($100) on EUR/USD with a 50-pip stop, where each pip is $10 per standard lot. Position size = $100 ÷ (50 × $10) = 0.20 lots. If the trade hits your stop you lose exactly $100 — no more.
Frequently asked questions
What percentage should I risk per trade?
Most professional traders risk between 0.5% and 2% per trade. Risking 1% is a common, sustainable default — you would need 100 consecutive losses to blow the account.
Are the pip values live?
Yes. For non-USD-quote pairs and gold the calculator fetches live exchange rates to compute the exact pip value, falling back to a close approximation if the feed is briefly unavailable.
Is this position size calculator free?
Completely free, with no sign-up. Bookmark it and size every trade consistently.