self guitar repair advice

When i go up to the 12th fret the tuning is slightly sharper than the open strings. Just barely. Not a whole half step. Its hard to hear a difference. But there is a slight one.

Is there a way to fix that?

It's the intonation and it depends on what sort of guitar you have so as I don't know what guitar it is I'd say look here http://www.wikihow.com/Set-Your-Guitar's-Intonation or google

You're talking about your electric I suppose? It is the intonation either way but its pretty easy to fix on your eletric.

Yup,tis the intonation.dont have much exp with intonation,unless you have a whammy bar.

If it's sharp at the 12th fret, you want to move the saddle back towards the tailpiece (a tiny bit).

If it's acoustic, you need a compensated saddle.

the harmonic on the 12th fret should be the same pitch as the string fretted at the 12th fret. if they aren't the same pitch, then the intonation is off.

intonation is set by adjusting the bridge position longitudinally (basically, the distance between the nut and the bridge saddle).

so if you have, say, a stratocaster, this is easy because each string has its own saddle. electric guitars with tune-o-matic bridges have individual saddles on the bridge. other guitars like my brother's acoustic don't have such adjustments...

thanks everyone.