Odds... What's the best way to calculate?

I'm sure this question has been asked many times but I have to ask it again. I'm realitively new to texas hold em in that I have just started trying to really develop the math side of my game and not play totally on instinct. I have several odds calculators that I have down loaded and use them to check the "equity" calculations I make in my head. Problem is I'm almost always wrong. I had hold em drill sergeant or something like that and i can NEVER get the hand equity right... is there a difinative formula to use? how do I calculate the hand equity when I'm ahead especially after the river? assuming i know and understand the rules of 2 and 4 and the basic formula of Z:1 Z=(X/Y)-1:1 X=unknown cards Y=outs. where am I going wrong???

Difficult to say. I think we need an example to see where you go wrong.

you need to understand the range of hands you could be possible up against to work out eqwuity


download this program

pokerstove

the normal odds formula of X:Y will give you the times something wont happen to the times something will happen

47 unseen cards, so you have 10 outs ....47 cards you dont know minus the 10 you know will help

37 unseen : 10 seen so you need to convert it to 1 so divide both sides by 10

3.7:1

3.7 times it wont happen to 1 it will

so then factor in pot odds and whatever else, i think thats more important than equity, but pokerstove will give you resulst for equity, im not sure how to calculate it though

Odds: 3.7:1 equals Factor 4.7:1
Maybe thats where you go wrong.

Ok... I can calculate hand eqiuty as far as outs vs. unknown cards go and get that ratio and even convert it to a percentage if I want to. I have a formula X:1 X= (Y/Z)-1 Y=unknown cards Z=outs. This formula very accutarely calculates odd post turn but does not seem to work post flop. I was looking for a similar formula to figure the odds post flop. The rules of 4 and 2 are accurate enough to a point then they skew about 7 points...there's also a method to compensate for that. I just want to explore simple math formulas at each stage of a hand to calculate odds... for me it's easier to do the formula in my head than to simply memorize an odds table.

I will check into pokerstove. I have heard alot of good things about it.

thanks to all who responded thus far