How do I calculate lot size for a prop firm challenge?

Divide the dollar amount you want to risk by the stop loss in pips multiplied by the pip value per lot. Risking $1,000 with a 20-pip stop on EUR/USD, where one standard lot is worth $10 per pip, gives 1,000 / (20 × 10) = 5 lots.

How much should I risk per trade on a funded account?

Many traders keep risk per trade to a fraction of the daily loss limit, often 0.5% to 1% of the account, so several losing trades in a row cannot breach the daily limit. This calculator warns you when one trade uses more than the share of the daily limit you set.

How do I size futures contracts like NQ or ES?

Convert the stop into ticks and multiply by the tick value. NQ moves in 0.25-point ticks worth $5, so a 20-point stop costs $400 per contract. With $400 of risk you can trade one NQ or ten MNQ contracts.

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Position size calculator for prop traders

Turn your risk per trade and stop loss into the right lot size or number of futures contracts, and get warned before one trade puts your daily loss limit at risk.

Trade setup

Account balance ($)

Instrument

Risk as

Risk per trade (%)

Stop loss (pips)

Current price

$ per point for 1 lotCheck your broker's contract size; it varies.

Tick size / tick value ($)

Prop firm guardrail

Daily loss limit (%)Enter 0 to skip the check.

Max share of daily limit per trade (%)

Position size (lots)

Amount at risk

—

Actual risk at this size

—

Value per pip, 1 lot

—

Mini / micro lots

—

Share of daily limit

—

Estimates only. Contract sizes, pip values and commissions vary by broker and platform. Confirm the specifications in your trading platform before you trade.

How to use the position size calculator

Enter your account balance, choose an instrument and set how much you want to risk, either as a percentage of the balance or a fixed dollar amount. Add your stop loss distance in pips (forex and gold) or points (indices and futures). The calculator returns the largest position that keeps your loss at the stop within your risk, rounded down so you never risk more than planned.

The guardrail compares that risk with your firm's daily loss limit. Set the share of the daily limit you are willing to put on one trade, and the calculator warns you when a trade goes over it.

The formula

Risk in dollars = balance × risk %.
Lots = risk ÷ (stop in pips × pip value per standard lot).
For USD-quoted pairs such as EUR/USD, a standard lot is worth $10 per pip. For USD/JPY it is 1,000 ÷ the current price; for USD/CAD and USD/CHF it is 10 ÷ the price.
Gold: a standard lot is 100 oz and one pip is a $0.10 move, worth $10 per lot.
Futures contracts = risk ÷ (stop in points ÷ tick size × tick value), rounded down to whole contracts.

Worked example

Forex: a $100,000 challenge risking 1% ($1,000) with a 20-pip stop on EUR/USD. $1,000 ÷ (20 × $10) = 5.00 lots. With a 5% daily limit ($5,000), that trade uses 20% of the day's allowance.

Futures: a $50K account risking $400 with a 20-point stop on NQ. NQ ticks are 0.25 points worth $5, so the stop costs 80 ticks × $5 = $400 per contract. You can trade 1 NQ, or 10 MNQ at $0.50 per tick.

Common position sizing mistakes

Sizing from the account size instead of your current balance after losses.
Forgetting that pip values change with price on pairs where USD is the base currency.
Risking most of the daily limit on one trade, so a single slip or gap fails the challenge.
Ignoring spread and commission, which add to the real loss at your stop.

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