I have noticed that a few currency pairs induce me to loose or gain more money than others, even when the amount of points gained or lost would be the same.

For example:
If I sell EURJPY and set a stop loss at 200 things, I can loose $500
But if I market USDCAD and set a stop loss at 200 points, then I could only loose loose $100.

How can I estimate about how much a point can induce me to loose or earn for any specific currency pair?