The soprano, or “standard” ukulele, is the only size there was from the 1880s up until the 1920s or so. It has an overall length of 21″ (see FAQs for other dimensions) and is normally tuned to ADF#B (the “old’, or “Canadian” tuning) or the increasingly universal GCEA (“my dog has fleas”). The soprano ukulele is still the most popular size, although these days most serious amateur and professional “uke” players are stepping up to a concert (23″ long) or a tenor (26″ long.) The soprano most often has 12 frets, with the neck joining the body at the 12th fret.
The concert-sized ukulele came about in the 1920s with the demand for a fuller-sounding ukulele that could fill an auditorium or hold its own in an ensemble. The concert typically measures 23″ in length (see FAQs for other dimensions), traditionally has a 15-fret fingerboard joining the body at the 12th fret, and has a fuller, richer and slightly louder sound than the soprano (“standard”) size. It is tuned the same as a soprano, GCEA.
The tenor-sized ukulele is tuned GCEA, just like the soprano and concert sizes, but has a very full, rich tone quality, wider-spaced frets (although the neck is not much wider) and, typically, a 19-fret neck joining the body at the 14th fret with an overall length of 26″. These days, it is often found in a low-G tuning, giving it a deeper, more guitar-like sound. (“Somewhere Over the Rainbow” by Israel Kamakawiwo’ole is a good recorded example of this tuning). Professional ukulele players most often choose the tenor size these days because of its tone, the multitude of chords and keys that can be played on it, and the excellent sustain and intonation that it offers. The tenor ukulele can be found in a 6-string version, which sounds richer and fuller but can be picked like a 4-string, and an 8-string version which doubles up all 4 of its strings for an amazingly full strummed sound that’s extremely popular for accompanying vocals or for rhythm accompaniment.
The baritone ukulele is the largest instrument of the ukulele family, and is not tuned like the other sizes, but more like a 4-stringed guitar (although special sets of strings are available that allow it to be tuned like a regular ukulele, in either low or high “G” tuning.) Arthur Godfrey popularized the baritone uke in the 1950s, and it can often be found in ukulele ensembles, rounding out the mid-bass tones. Makes a mighty fine solo instrument, too!