UkuScales offers you the largest ukulele scales archive available online. Although there are a vast amount of scales listed here on UkuScales, it is very easy to use and it is completely free. Scales are available for three popular tunings. The default tuning is GCEA (standard or C tuning) but ADF#B (soprano or D tuning) and DGBE (baritone tuning) are available as quick tunings. Advanced users can click on the notes in peg heads to even create your own tuning!
After you have selected your tuning you need to first select a root note or tonic. The final step is to then select one of the many ukulele scales available. UkuScales contains all the popular tunings as well as some more exotic ones. Enjoy!