How to calculate lots for a given risk

Hello

If I want to asses to a trade a given $ risk in my denomination, how do I calculate the # of unit to sell or buy

My account is in CAD
My risk per trade 100$

How many units of CHF.JPY should I apply If
entry is 107.745
Stop: 107.500

Risk = 0.245

I'm not looking for the number, but for an explication of the formula
I need to modify my Excel calculation because I was not taking care of the risk in my denomination ( Canadian dollars)

Any help appreciated
Martin

When you trade XXX/ZZZ. The price is in ZZZ. So here CHF/JPY is in JPY. Your risk is 0.245 JPY.
1- You take the last quote for CAD/JPY to convert your risk in JPY. Now CAD/JPY=96.88.
2- You multiply by the CAD risk you want 100 CAD = 9688 JPY
3- You divide by the risk in JPY from your entry to your exit: 9688/0.245 = 39542.86
4- 1 micro lot is 1000 units so you divide by 1000: 39542.86/1000=39.54286
5- You drop the decimals: 39 micro lots

If the quote is in /CAD, take the reciprocal. E.g. for EUR/AUD, take 1/(AUD/CAD)

Now do the homework again because I omitted to add the spread you have for CHF/JPY to the risk

Try this calculator:
http://www.earnforex.com/position-size-calculator

Thanks pipmeup

Very well explain.
OK for the spread as I was already taking care of it.
Will modify my Excel worksheet this weekend

Martin