Lot size calculator based on risk per trade and stop loss

The money at risk equals your balance times your risk percent. The tool takes the pip value per lot for your pair, then divides your risk by pip value times stop loss in pips. Lots rounds down to a size your broker accepts, usually in steps of 0.01.

On USD 500 at 2% risk, you can lose USD 10. A 40-pip stop on EUR/USD at USD 10 per pip per lot gives 10 ÷ 400, or 0.025 lots, which rounds down to 0.02. That small rounding works in your favour, since it reduces your risk slightly below your limit.

This lot size calculator repeats those steps instantly.

Many experienced traders risk 1% to 2% of their balance on a single trade. Ten straight losses at 2% leaves about 82% of your balance, and ten at 10% leaves about 35%. Losing streaks happen to everyone, so the rule exists to keep you in the game long enough to learn.

Small balances make this harder. On USD 50 at 1%, your risk is USD 0.50, and a 20-pip stop needs 0.0025 lots, below most brokers' 0.01 minimum. A cent account solves that problem, because positions go smaller. Our forex broker table shows the entry cost of each account.

A 1% rule also makes your results easier to judge.

Set your stop where the trade idea is proven wrong, then let this tool size the position from it. Working backwards from the lot size you want and squeezing the stop to fit is a common cause of losses, since normal market noise then takes you out.

A wider stop means a smaller position with the same dollar risk. A 50-pip stop on USD 1,000 at 1% gives 0.02 lots, and a 10-pip stop gives 0.1 lots. Both lose USD 10 if the stop is hit. Check the margin for your position with the margin calculator before you trade.

Each of those 2 trades carries the same risk.