This free forex lot size calculator returns the exact MT4 or MT5 lot size to enter based on your risk percentage and stop-loss distance in pips. Works for any FX pair — EURUSD, GBPUSD, USDJPY, and more. Just adjust the pip value for the instrument (typically $10 per pip per standard lot on USD-quoted majors). For XAUUSD gold, use our dedicated XAUUSD Lot Size Calculator.
Forex Lot Size Calculator is part of the free Aurex Trader calculator suite — 23 browser-based tools for gold (XAUUSD) and forex traders. Nothing is installed, no account is required, and every calculation runs locally in your browser.
Formula: Lot Size = (Balance × Risk %) ÷ (Stop-Loss Pips × Pip Value)
1 standard lot = 100,000 units of the base currency. 0.10 lot = 10,000 units (mini lot). 0.01 lot = 1,000 units (micro lot). Most retail accounts trade in micro lots to keep risk manageable.
For a standard 1.00 lot on any USD-quoted major (EURUSD, GBPUSD, AUDUSD, etc.), the pip value is exactly $10. For pairs with a non-USD quote (like USDJPY), the pip value is approximately $10 but fluctuates — check your broker's calculator.