Every time I make a cake covered in fondant, I guess how much I will need, color it and wind up with quite a bit left over.

Is there a method or way to better know how much fondant is needed to cover a tier so I don't feel like I am wasting so much fondant?

Wilton has a guide in all of their yearbooks and in the insert from their fondant so I'm sure it must be posted on their website. I always use a little less than what they recommend, though, because I was wasting a lot of fondant. Not sure if I roll it thinner than they recommend of it it's a sales tactic but regardless, it is a very handy guide.

These amounts are based on a double layer (4") cake and AFTER trimming excess fondant...

Satin Ice
Cake Diameter Net Weight
6" 10 oz. (.63 lbs.)
8" 12 oz. (.75 lbs.)
10" 18 oz. (1.13 lbs.)
12" 24 oz. (1.5 lbs.)
14" 48 oz. (3.0 lbs.)


Choco Pan
Cake Diameter Net Weight
6" 8 oz. (.5 lbs.)
8" 10.5 oz. (.66 lbs.)
10" 13 oz. (.81 lbs.)
12" 25.6 oz. (1.6 lbs.)
14" 48 oz (3.0 lbs.)

http://forum.intotheoven.com/fondant/2-how-much-fondant-do-i-need-cover-my-cake.html

http://www.wilton.com/decorating/fondant/fondant-coverage-chart.cfm