There are four common sizes of ukuleles. It should be noted that there is no set standard and that some ukuleles fall in-between the size definitions given below, particularly on the lower end of the scale.

Soprano Ukulele: This is the most traditional ukulele size and most associated with Hawaiian music. They are typically about 21" long. Because the strings typically have less tension they do not stay in tune as well as other ukes. Really cheap ukuleles are usually Sopranos. Although the most popular, this is probably not the best type of ukulele to learn on.

Concert Ukulele: Typically 23 inches in length, the Concert Ukulele typically sounds much better and maintains its tune better than the Soprano Uke. They look very similar.

Tenor Ukulele: Typically about 26 inches in length, Tenor Ukuleles have a fuller and richer sound, at least if they are of good quality. They project better and have a warmer tone, making them preferred by many live performers.

Baritone Ukulele: Baritone Ukuleles are about 30 inches in length and produce a sound more similar to that of a guitar. In addition they are tuned differently; the same as the bottom four strings of a guitar or bass. This makes the Baritone Ukulele a favorite among guitarists and bass players interested in playing the uke.

A version of the Baritone Ukulele known as the Bass Ukulele or U-Bass is taking the market by storm, thanks to special new Aquila strings that have a rubbery feel but have a metal core which helps them stay in tune and last longer.

Most of the Bass Ukuleles that Audio-Depot has sold went to bass players looking for a travel guitar or a unique instrument for the stage. However, the rubbery feel of the strings makes them a favorite for persons attempting to learn bass guitar, which can cause painful callouses due to the heavy wound metal strings. It also reduces hand cramping since the distances that the hand must stretch are smaller than that of a bass guitar. Easy and fun to play, the Bass Ukulele is quickly growing in popularity.

On the opposite end of the spectrum, Sopranissimo Ukuleles are smaller than Soprano Ukuleles and are often intended for children. Cheaper versions will be made of plastic while better Sopranissimo Ukuleles will have a carbon fiber back and solid wooden top. These better-made ukuleles can also withstand more abuse from children. Sopranissimo ukuleles are sometimes purchased by musicians looking for a small travel or practice ukulele but can be difficult for those with larger fingers.

The quality of a ukulele, like that of an acoustic guitar, is usually associated with solid wood versus laminate/plywood, the kind of wood it is made from, and the resulting sound quality and beauty of the instrument. As a result of professionals and hobbyist collectors taking a greater interest in this instrument, many higher quality ukuleles today are color stained and highly glossed and some have cut outs or even a more decorative shape not commonly associated with ukuleles.

For ukulele tunings, see the information written in the section Ukuleles, Acoustic & Electric