Position size in forex equals dollar risk divided by stop distance in pips times pip value. Institutional desks rarely exceed 1% risk per trade. A $10,000 account risking 1% with a 30-pip stop on EUR/USD trades approximately 0.33 standard lots.
Pick your account size. Pick the percent you are willing to risk on the trade. Pick your stop distance in pips. The calculator returns the exact lot size that risks that dollar amount and not a penny more. This is the same calculation institutional desks run pre-trade, the calculator just removes the manual step.
Position Size Calculator
Why position sizing is the only variable that wipes accounts
Three things determine whether a trader survives long enough to find their edge. The first is strategy expectancy, which is binary, either you have a positive expected value system or you do not. The second is psychology, which is mostly fixable through process. The third is position sizing, which is the only one of the three that mechanically blows accounts inside a single trade. Position size is not optional discipline, it is structural protection against the strategy not working today.
The math on this is straightforward. On a 50% win rate strategy, the probability of a 6-trade losing streak inside 50 trades is roughly 35%. A 7-trade streak shows up about 18% of the time. Anyone who has traded for a year has hit a 6-7 trade losing streak, the only question is whether their position sizing left enough capital to keep trading after it. At 1% risk per trade, a 7-loss streak takes the account to 93.3% of starting capital. At 3% risk per trade, the same streak takes it to 80.7%. The drawdowns compound asymmetrically because winning back from 80% to 100% requires a 24% gain, not 20%.
The institutional position sizing rules the desk uses
Three rules govern every position taken at the desk. Maximum risk per trade is 1% of equity on standard setups, 1.5% on A+ setups with three or more confluences agreeing. Maximum risk per correlated cluster is 2% (so a long EUR/USD plus long GBP/USD plus long AUD/USD counts as one cluster against the same dollar weakness thesis, not three separate trades). Maximum daily drawdown is 3%, at which point the desk stops trading regardless of the setup quality on the chart.
For prop challenges the math is even tighter. A 5% daily loss limit and 10% overall drawdown is the standard, which means 1% per trade with a 3-trade daily limit and a 6-trade weekly limit is the survivable sizing. Anything bigger turns the challenge into a coin flip on a single news event.
Recommended brokers for live execution
Frequently asked questions
What is a good risk per trade percent?
Institutional desks rarely exceed 1% per trade. Retail funded accounts and prop challenges typically cap at 0.5% to 1.5%. Anything above 2% per trade carries career risk on a typical 20-trade losing streak (10-15% of all trade sequences hit a 6-loss streak). The calculator defaults to 1%.
How do prop firms decide allowed position size?
Most prop firms cap daily loss at 4-5% and max overall drawdown at 8-12%. Working backwards: if your daily loss limit is 5% and you take 5 trades a day, position sizing at 1% per trade leaves a buffer. Position sizing at 2% per trade and one losing day takes you out.
Why does the calculator ask for stop loss in pips?
Position size depends on the distance from your entry to your stop. A tight 10-pip stop allows a larger position for the same dollar risk than a 50-pip stop. The calculator inverts the formula: pick the dollar risk first, the stop second, the lot size falls out.
Is this calculator accurate for indices and gold?
Yes, the calculator handles forex pairs (standard and JPY), gold, silver, oil, and the main indices. The pip value math feeds the position size formula automatically.
Should I use this on every trade?
Yes. Position sizing is the only variable in trading that compounds linearly. Strategy edge compounds geometrically, risk compounds linearly, and getting position size wrong wipes the edge out faster than anything else does.
Related tools: Pip calculator · Margin calculator · Profit/loss calculator · Compounding calculator