on all of the websites i look at when it comes to setting the action/string height they always say measure at the 12th fret but on fender they say measure from the 17th fret.

so what should i measure from, the 12th or 17th fret?

Well I'm not sure if I'm missing something but what I've seen and done is capo the first fret, hold down the last fret and then measure the gap at the eighth fret. That gap will tell you what the action height is. Of course there are the issues of the neck relief and bridge height and which you decide to address in order to achieve the action height that you want. No matter what you do on your guitar just remember to use small adjustments. Measure, adjust and then measure again. It may mean retuning and screwing around a bit but this patience will reduce the risk of doing damage. Don't be afraid of working on your guitar, just be smart!

im sorry, i wasnt clear, i am not talking about truss rod adjustment i am talking about setting action.

Sorry dude actually now that I re read it again you were clear. According to the Fender Strat Handbook it says to measure at the 17th fret. It gives some slightly different recommendations for heights though based on neck radius.

Neck Radius String Height Bass side String Height Treble side
7.25 in 5/64 in 4/64 in
9.5 - 12 in 4/64 in 4/64 in
15 - 17 in 4/64 in 3/64 in

I'm not sure if you want those recommendations or if you're just wanting to simply measure the action but that's the info I have in my book. Best of luck with your tinkering!

Well everyone likes there action different. If I have a guitar set for blues-rock it is set medium low. If I want to fool around with shred techniques then it hits the frets and rises just enough not to buzz.