Forex Position Size Calculator
Size a forex trade based on your risk.
In pips
Default $10
Results update as you type.
How it works
Proper position sizing is the foundation of forex risk management, and this calculator tells you how large a trade to take so that hitting your stop-loss costs only the amount you are willing to risk. You enter your account balance, the percentage of it you will risk on the trade, your stop-loss distance in pips, and the pip value of a standard lot, and it returns the position size in lots and the dollar amount at risk. The logic works backward from risk: you decide the maximum loss you can accept, commonly one or two percent of your account, then size the position so that if the price moves against you by your stop-loss distance, the loss equals that amount. The calculation divides your risk amount by the loss per lot, which is the stop-loss pips times the pip value per lot. This disciplined approach protects your capital: risking a small, fixed percentage on each trade means no single loss can seriously damage your account, and it keeps your risk consistent regardless of the stop distance, since wider stops automatically produce smaller positions. Professional traders consider position sizing more important than entry timing for long-term survival. The default pip value of $10 per standard lot applies to many dollar-quoted pairs; adjust it for your pair and account currency. Enter your balance, risk, stop-loss, and pip value to compute the position size.
Lots = (balance × risk%) / (stop-loss pips × pip value per lot)
First the amount you are willing to risk is your account balance times your risk percentage. Dividing that by the stop-loss distance in pips times the pip value of one standard lot gives the position size in lots that keeps your loss at the stop equal to your intended risk.
Source:Forex risk management
We review all our tools from time to time to ensure accuracy.
Worked example
How to use this calculator
- 1
Enter your values
Enter account balance, risk per trade and stop loss.
- 2
Adjust the options
Adjust pip value per standard lot if they apply — sensible defaults are already set.
- 3
Read your result
Position size updates instantly as you type — no button to press.
Frequently asked questions
How do you calculate forex position size?
Multiply your account balance by your risk percentage to get the amount you will risk, then divide by the stop-loss distance in pips times the pip value per lot. The result is the lot size that limits your loss at the stop to your intended risk. The calculator does this from your four inputs.
Why size positions by risk?
Risk-based sizing ensures no single trade can seriously harm your account. By risking a small fixed percentage, such as one or two percent, on every trade, a losing streak causes only manageable drawdowns. It also keeps risk consistent: a wider stop-loss automatically yields a smaller position, so your dollar risk stays the same.
What percentage should I risk per trade?
Many traders risk one to two percent of their account per trade. Lower risk preserves capital through losing streaks and reduces stress, while higher risk grows the account faster but can deplete it quickly. The right level depends on your strategy, win rate, and risk tolerance, but keeping it small is widely recommended for survival.
How does the stop-loss affect position size?
A wider stop-loss, meaning more pips to your exit, results in a smaller position for the same dollar risk, because each pip is worth more money across a larger position. A tighter stop allows a bigger position. This inverse relationship keeps your total risk constant regardless of where you place the stop.
What pip value should I use?
The default of $10 per standard lot applies to many currency pairs quoted in US dollars. For other pairs or account currencies, use the actual pip value per standard lot, which you can find with a pip value calculator. Entering the correct pip value ensures the position size accurately reflects your intended risk.