Position Size Calculator

A position size calculator works out how many lots to trade so that hitting your stop-loss costs only the amount you chose to risk. Enter your account balance, risk percentage, stop-loss in pips and instrument, and it returns the risk amount, the position size in lots and units, and the pip value per lot.

How to Use the Position Size Calculator

1. Enter your Account balance and choose the Account currency.
2. Set Risk %, the share of your balance you are prepared to lose if the stop is hit.
3. Enter your Stop-loss (pips), the distance from your entry to your stop.
4. Pick the Instrument. Leave Exchange rate blank for the live rate, or press Live to see it.
5. Press Calculate.

Position Size Formula

Lots = (balance × risk % ÷ 100) ÷ (stop-loss in pips × pip value per lot)

• Balance × risk % ÷ 100 is the risk amount, the most you plan to lose on the trade.
• Stop-loss in pips is how far price can move against you before you exit.
• Pip value per lot is what one pip is worth on one standard lot in your account currency, for example 10 USD on EUR/USD.
• Units are lots × contract size, which is 100,000 for forex pairs.

Worked Example

You have 10,000 USD, risk 1% and place a 30-pip stop on EUR/USD.

• Risk amount = 10,000 × 1 ÷ 100 = 100 USD
• Pip value per lot = 0.0001 × 100,000 = 10 USD
• Lots = 100 ÷ (30 × 10) = 0.333, shown as 0.33 lots
• Units = 0.333 × 100,000 = 33,333

Widen the stop to 50 pips and the size falls to 100 ÷ (50 × 10) = 0.20 lots, so the money at risk stays at 100 USD.

Tips

Round the result down to a lot step your platform allows, often 0.01, so you never risk more than planned. Set the stop where the chart shows your idea is wrong, then let the calculator size the trade, not the other way round. Spread and slippage can add a little to the real loss.

Go deeper with the position sizing guide, risk management basics and stop-loss strategies. Then check the trade's payoff with the risk and reward calculator.