How Much Sugar to Add for Bottle Carbonation

[andy383]

I made a batch of Brando O's Graff but forgot to take an OG. I now want to bottle it but I don't know what to do for carbonation. Do I add sugar and how much? I'm pretty clueless so thanks in advance for the help.

 

[Nateo]

http://hbd.org/cgi-bin/recipator/recipator/carbonation.html

I think I carbonated my last cider to around 2.5 volumes, but I lost my notes.