Currently planning my son's birthday cake. I will need to cover a 10 inch sphere, about a 6 inch half sphere totally and the cake board in fondant. Looked at multiple websites but can't find out how to estimate for non normal cake shapes. Hopefully in the end I will have a surprise BB8 display cake for his party and maybe to enter into our county and state fair later this year.

Bump.

I found this although I've never used it:

www.wilton.com/cms-fondant-amounts-to-cover-cakes.html