Forex Lot Size Calculator
Lot size = (account balance × risk %) ÷ (stop-loss pips × pip value). The calculator does the math live — change any input, see the answer instantly.
- Standard lot = 100,000 units of base currency
- Mini lot = 0.10 (10,000 units)
- Micro lot = 0.01 (1,000 units)
- Most prop firms cap risk per trade at 1-2% of account balance
Risk in $—
Pip value (your lot)—
Lot size to use—
Position size (units)—
Why Position Sizing Matters for Prop Firms
Prop firms enforce hard daily and overall drawdown limits. One oversized trade can hit the daily DD limit and end your challenge instantly. The fix is mechanical: compute lot size BEFORE every trade based on stop-loss distance and a fixed risk percentage.
Recommended Risk Per Trade by Strategy
- Scalper (10-20 pip stops): 0.5-0.75% per trade
- Day trader (30-50 pip stops): 1-1.5% per trade
- Swing trader (100-200 pip stops): 1-2% per trade