Enter your account size and the drawdown you are willing to sit through. The calculation works backwards from there: how far price can travel against you before the thesis is dead, how many pips that is, and what total position survives it.
Fill in all four fields to see the position plan.
Pip values are approximations based on the latest cross rates and assume a standard lot of 100,000 units. Confirm contract size with your broker before sizing. This is arithmetic on the parameters you entered, not a recommendation.