The baritone is the largest of the four primary ukulele sizes. Aside from size, the big difference between a baritone and the other three sizes is tuning. I go into the theory below, but all you need to know is that baritone ukulele are tuned to a lower pitch than a standard ukulele.
The baritone's large size and lower tuning give it a deep, rich tone that's unlike any other member of the ukulele family. However, their nonstandard tuning means you can't easily use them with traditional ukulele chord sheets and song books.
For this reason I wouldn't recommend a baritone ukulele for a beginner. Baritone Tuning Vs. Standard Ukulele Tuning A baritone ukulele is tuned D-G-B-E and a standard ukulele is tuned G-C-E-A.
The pitch of a baritone uke is five half steps lower than a standard ukulele. The relationship between the strings stays the same, but the notes are lower. This means that standard ukulele chord shapes will work on a baritone, but they will be lower in pitch.
For example, if you form a standard D-major chord shape on a baritone's fingerboard and strum, you'll hear a G-major chord, which is five half steps down in pitch. To look at it another way, if you placed your finger across the fifth fret of a baritone ukulele and strummed, you'd be playing the same notes as a standard ukulele.