Ukulele chords can be used for playing guitar. Lots of times, when I am out and about, people will say to me, "LA, we know you play the ukulele and write a lot about it, but we have a guitar--can you help us find a way to play ukulele music on our guitar?" My first reaction was to think, "why not just get guitar music?" Then I thought about all of the great Tin Pan Alley songs that came with ukulele chord diagrams and all the wonderful ukulele song books now available and I could see the merit of their requests. I also thought that the situation could arise where a guitar player might want to play along with a ukulele player and use the ukulele music, so playing ukulele music on a guitar is definitely a very reasonable endeavor.
To play ukulele chords on your guitar, all you have to do is get a capo and place it on the fifth fret of your guitar and ignore the low E and A strings--that is, play only the four strings that are tuned to the highest notes. If you know your guitar chords, you can use the two lowest strings for bass runs. This setup assumes that the ukulele chords are for a uke that is tuned in the key of C. Some sheet music indicates that the uke is to be tuned in the key of D and in this case the capo should be placed on the seventh fret. If the tuning is in D with a capo on the first fret of the ukulele, the capo on the guitar should be placed on the eighth fret. Less often, the chord diagrams will be for a ukulele tuned in the key of Bb, requiring the guitar capo to be placed of the third fret. The note of the third string of the ukulele gives the name of the key to which the ukulele is to be tuned. Occasionally there will be no indication of how the uke is to be tuned. In this case you will have to observe the key signature of the song and adjust the capo so that the chord played with the capo sounds like the corresponding guitar chord for the key the music is written in. In other words if the song is in Eb, the first chord of the chorus will usually be Eb. Adjust the capo so that the uke chord played with the capo sounds like the guitar
Eb chord played without the capo. This will place the capo in the proper position.
If you wish to sing with the guitar and are not able to hit all the notes due to the fact that the music was arranged for a female vocalist and you are a baritone, you may transpose the song to a lower key just by moving the capo to position closer to the nut. The same thing will work in reverse if you are a soprano.
Sadly there is no maneuver that will make a guitar sound like a ukulele because the sound decays much more slowly on a guitar than on a ukulele which sounds closer to a banjo and is therefore better suited to the great traditional jazz songs of the 20's and 30's.
If you crave more volume than a ukulele makes, see the discussion of the tenor banjo and tenor guitar found on this site.