Core formula
Risk amount = account balance x risk percentage.
Raw lot size = risk amount / (stop loss distance x contract size x currency conversion rate).
Rounded lot size = rounded down to nearest broker lot step.
Stop loss distance and conversion
Stop loss is entered in pips or points depending on the instrument page. Currency conversion is applied when account currency differs from USD sizing basis.
Minimum lot handling
If calculated lot size is below minimum lot, the calculator shows a warning and avoids forcing a higher risk by rounding up.
Why broker specifications matter
Broker contract size, lot step, minimum lot, and point value can differ across symbols and brokers. Always verify symbol specifications in your trading platform before placing a trade.
Limitations
Results are estimates and do not include spread widening, slippage, swaps, commissions, margin calls, liquidity changes, gaps, or execution latency.