Is there any software out there for estimating filament used?

First, slice the file so that you get the cubic centimeter reading that estimates how much plastic will be needed.

The volume of a cylinder, which is what the filament is, is:

V = pi * r^2 * h

Where r is roughly 0.875mm (depending on your filament's diameter/radius), so we can solve for h (which is the length of filament needed)

Also 0.875mm is equal to 0.0875cm

h = V/(pi * r^2)

h = V/(pi * (0.0875cm)^2)

h = V/(0.024cm^2)

Inverting that:

h = V * 41.667 cm^-2

This will vary with the radius of the filament, but it should give you a good estimate.

Note:  Make sure to get a good measurement, because the difference in filament diameter changes the number.  Filament with a 1.72mm diameter will give you a multiplier of 43 instead of 41.

Well crap.  Haha.  I guess that is the easier way to go about it.

Here's what it looks like: