Originally Posted by Vigo_Carpathian
What about taking into account the residual sugar in the beer itself?
Assuming it got to final gravity, there is next to no residual fermentable sugar in the beer.
A bigger thing to consider is the temperature of the beer. The lower the max temp during or after fermentation, the more dissolved CO2 will be left in solution. This can affect final carbonation. I believe it is accounted for by an input in the calculators, but I'm not sure