Tunings

The standard tuning for the Ukulele is GCEA. It's used on instruments of varying size but you will also find the Soprano tuning (ADF#B), typically on shorter instruments, and occasionally the DGBE tuning on Base or Baritone Ukuleles.

The Base tuning of DGBE is visible on the neck, 7 frets below the GCEA. If you use a capo to cinch the strings at fret 7 you can play a standard GCEA Ukulele as though it were a base DGBE. But on most Ukulele's you'll run out of fretboard very quickly and of course the tone will be higher than desirable. (Good for practise though.)

However, as an aside, the standard Guitar EADGBE tuning has DGBE as the first 4 strings. So it can be played as a base Ukulele by simply ignoring the uppermost 3 strings. If you have a capo then you will find the GCEA tuning on those same four strings at fret 5 on the Guitar.

So unlike most Guitar tunings, which are not mere transpositions of the frets down the neck, the Ukulele is the same layout for all three tunings.

This is not immediately obvious for the same reason stated in The Problem. The Tabs that are traditionally used do not allow you to see this relationship.

Below we can see two diagrams one for GCEA and one for DGBE of the same 7th chord. I have drawn attention to where they overlap.

 

The DGBE tuning is 7 frets below the GCEA. We can see that this means the shapes have also moved over by 7 notes. (1 fret does equal 1 note).

The GCEA line is highlighted here and you can see the shapes in the upper GCEA tuning are identical at this level.

This means that if you learn to play one tuning of the Ukulele - then you can move to another without relearning new shapes or offsets. But you will have to retrain which notes are associated with which shapes. (If you were used to playing GCEA then an A shape would become an E shape in the DGBE tuning).