Need tips on Position Size Management

I having a little bit of a hard time handling MM when it comes to converting pips into account currency value.

I want to place my SL and TP at strategic places of where price will likely turn (SL just after likely turn and TP just before likely turn).

Is there a way to calculate position/lot size within MT4 (or Excel perhaps) based on where I place SL? For example, I only want to risk 2% and I plan to put SL above previous resistance for a sell order - how then can I calculate the appropriate lot size? (visual drawing example below)

I have tried a few things on Excel before but they were very slow and awkward.

Thanks for any suggestions/tips/ect.
..

Here is something you can try, however, I'm not sure it does quite what you want:
This script.
http://www.forexfactory.com/attachme...7&d=1314895656
from post:
http://www.forexfactory.com/showthre...44#post4920744

Thanks mate. I'll check them out.

I am currently checking this one out.

Please be aware that for JPY pairs it will calculate a wrong lot-size.
On other pairs it is ok.

For USD pairs, this formula is good enough:
money_to_loss = AccountBalance() * risk;
lotsize = money_to_loss/sl/10

Example:
Balance = 20.000
Risk = 2 %
StopLoss distance in Pips = 30

Money you are ready to lose: 2 % = 20.000 * 2 / 100 = 400

Lotsize = 400 / 30 / 10 = 1.33

If you verify this Lotsize, you will see that 1.33 lots translate to $13.33 per Pip.
30 Pips * $13.33 = $399.90 , which are almost 400 Dollars
-----> this little formula is good enough for USD pairs when the account is held in USD.

Sangmanes order entry program is pretty darn good.