Prop Firm Calculators

Prop firm position size calculator

Find the lot size that risks exactly the share of your balance you choose, and see how many losing trades in a row your daily loss limit and maximum loss can absorb.

Prop firm position size calculator by PropSim

The formula

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

The result is rounded down to your broker's lot step, so the money at risk never exceeds your target. On a $100,000 account risking 0.5% with a 20-pip stop on EUR/USD ($10 a pip per lot), that is $500 ÷ $200 = 2.50 lots.

Pip value

For pairs quoted in US dollars (EUR/USD, GBP/USD, AUD/USD) on a USD account, one pip on 1.00 lot is worth $10. For other pairs, metals, indices and crypto it depends on the contract size and the exchange rate, so take it from your broker's contract specification.

Why risk per trade matters on a challenge

The losing-streak lines show how much room a risk level leaves. In the PropSim Prop Trading Index (week of 2026-10-19), the median risk per trade was 0.59% of the balance for accounts that cleared a phase and 0.78% for accounts that failed. That describes accounts on the PropSim platform and is a difference between two groups, not proof of cause.

Questions

How much should I risk per trade on a prop firm challenge?

There is no single right number. Many traders risk between 0.25% and 1% per trade so that a losing streak stays well inside the daily loss limit. Use the calculator to see how many losses in a row your choice allows.

What is the pip value of 1 lot?

For USD-quoted forex pairs on a USD account, $10 per pip per standard lot. Other symbols differ; your broker's contract specification lists the value.

Why does the calculator round the lot size down?

So the money at risk is never more than you chose. Rounding up by even one lot step would risk slightly more.

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<p><a href="https://propsim-enterprise.github.io/prop-firm-calculators/position-size/">Prop firm position size calculator</a> by <a href="https://propsim.markets">PropSim</a></p>

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