calculating lot size based on money to risk, not %

hi all,
i'm looking for a script or an ea that will calculate my lot size based on money to risk, not based on account % to risk:

i have the stop loss let's say 50 pips, i'd like to know my lot size if i'd like to risk 75$,

i trade a lot of cross, 29, so caluclating lot size every time it's like a job!

thank's a lot!

This is the best one out there IMO :
http://www.earnforex.com/position-size-calculator

thanks Shabs, it seems very good,
i'll try it

Try this indicator
http://codebase.mql4.com/source/22814

The following instructions are copied from a recent e-mail of mine. This script allows TradeRisk to be entered as a number of dollars, e.g. $200

I've attached a script that should perform your requested task (download it into your ....[MT4]/experts/scripts folder, and then restart MT4). The calculations were copied from VO-Pro, hence they should be correct, but I've performed only some very basic testing. Please test it further yourself, and satisfy yourself that it works as you'd expect it to, before you run it on a live account. In other words, use it at your own risk. The parameters work as follows:

TradeRisk can be entered as a number of lots, $ or %, exactly like VO-Pro. You can also add E, B or F (upper or lowercase) to nominate % of Account Balance, Equity or Free Margin. The only difference is that the position weights (25,25,25,25 in your example) need to be entered in the VolWeights parameter (I have used 1,1,1,1 — i.e. same ratios, therefore effectively the same thing).

BuyOrSell — enter B or S (upper or lowercase) for market buy orders, or market sell orders, to be created.

SLpips, TPpips — pips away from entry price. The TPpips value is then multiplied by the value in TPmultiples. Hence setting SLpips to 10, TPpips to 10, and TPmultiples to 1,2,3,4 will give a SL=10, and TPs=1x10=10, 2x10=20, 3x10=30, 4x10=40.

TradeComment, TradeMagicNo, ArrowColor — optionally enter a trade comment, magic number and/or arrow color, for your orders.

AdjustForSpread — this should work the same as in VO-Pro.