One cool thing abount the guitar is the CAGED system. 
Start for example with the chord A. In the word CAGED G comes after A.
Now we know how we play A on open strings, whereever you lowest finger is(fret 2 in our example), place a capo or bar it. 
Now play G, the next letter in CAGED. It's Still the A Chord. 
Now place you capo or bar where you lowest finger is(fret 5) and play the E chord. It's STILL the A chord. 
The only EXCEPTION is between D and C( in CAGED...CAGEDCAGED).
Here place your capo or bar one fret up the neck. 
It's a Great way to remember ways to place chords.