Start with four: C, Am, F and G. In the key of C those are the 1, 6m, 4 and 5, and they cover a huge share of pop, folk and worship songs. Add the rest as songs ask for them.
0 0 0 32 2 2 04 4 4 22 0 1 00 2 3 22 1 0 03 2 1 12 0 0 04 2 2 22 2 1 00 4 3 22 1 2 0If a song is in a key that's awkward on uke, the transpose chart moves it somewhere friendlier.
Chartless listens to whatever is playing and shows the chords live, with shapes for ukulele as well as guitar. The live chart is free.
More: chord finder · how to tune a ukulele · baritone uke chords · banjo chords · what key is this song in · chords by ear · all guides.