Widening a gold stop from 25 pips to 50 pips seconds before CPI without halving your lot size silently doubles your monetary loss. Sizing from stop distance first—and letting lot size be the output—keeps every setup at an identical 1R risk unit.
1. The universal MT5 tick-value sizing formula
Never hardcode "$10 per pip"—that shortcut fails on XAUUSD, JPY crosses, US100, and non-USD deposit currencies. Always use MT5 contract specifications:
Lots = FloorToStep( RiskMoney / ( (|Entry - StopLoss| / TickSize) × TickValue ), LotStep )
2. Worked XAUUSD example ($100 fixed 1R risk)
With Entry = 2658.40, Stop Loss = 2654.80 (distance = $3.60 = 360 points at 0.01 TickSize), and TickValue = $1.00 per 1.00 lot per 0.01 tick: 1.00 lot risks $360.00. For a $100.00 risk cap, raw volume = 100 / 360 = 0.2777 → rounded down to broker LotStep (0.01) = 0.27 or 0.28 lots.
3. Pre-submit draft lines prevent fat-finger 1-click orders
- Set your fixed risk budget ($100 or 0.5% of equity) once before the session.
- Preview dashed Entry and Stop-Loss draft lines directly on the chart—zero broker order is transmitted while planning.
- Drag the Stop-Loss line wider or tighter behind structure; verify lot size recalculates in milliseconds within MinLot/MaxLot/LotStep.
- Click Send only when stop placement, R-multiple reward, and margin check look clean.