Forex lot size formula
Position size = amount at risk ÷ (stop loss in pips × pip value per standard lot). Amount at risk is the account balance multiplied by the selected risk percentage.
Position size example
For a $10,000 account risking 1%, the risk budget is $100. With a 20-pip stop and a $10 pip value per standard lot, $100 ÷ (20 × $10) equals 0.50 standard lots.
Standard, mini, and micro lots
One standard lot is commonly 100,000 base-currency units, one mini lot 10,000, and one micro lot 1,000. Broker contract specifications remain the source of truth.
What the estimate excludes
Spread, commission, slippage, gaps, currency conversion, and broker minimum increments can change actual risk. Gold, indices, CFDs, and crypto use different tick or contract values.
Pip value and lot size
Pip value links price movement to money risk. It changes with position size and can also depend on the pair, quote currency, account currency, and current conversion rate.
Use stop distance before leverage
Choose a technically meaningful invalidation point first. The Forex risk calculator then reduces lot size when the stop is wider, instead of moving the stop to justify a larger position.