Tools Library · Calculator 1

Position-Size Calculator

How big can this trade be, if the stop is hit and you only want to lose a fixed slice of your account? Type the numbers in — the maths stays visible.

Your trade

The money actually in the account.
1% is the usual starting point. 2% is already aggressive.
Assumes the quote currency is USD. Spreads, commissions and slippage are not included.
Where you plan to get in.
Where you admit you were wrong and get out.

Fill in the numbers and press calculate — or just edit a value, the answer updates as you type.

The maths, in the open

Step 1 — risk amount: balance × risk %. Step 2 — distance: |entry − stop|, converted to pips for FX (÷ 0.0001, or ÷ 0.01 for JPY pairs) or left in dollars for gold. Step 3 — size: for FX, units = risk ÷ (pips × pip size), lots = units ÷ 100,000 (one standard lot = 100,000 units of the base currency). For gold, lots = risk ÷ (distance in $ × $100 per lot), because one lot is 100 ounces and a $1 move is worth $100 per lot.

Stackbot's house rule: decide the stop first, then let the maths decide the size — never the other way round. The full reasoning lives in the guide: Position sizing for algo traders →

Educational tool, not financial advice. It sizes a single trade against a fixed stop; it cannot protect you from gaps, slippage or a broker's margin rules.