If we assume you’ll have 20 guests at your wedding (a nice number that’s easy to multiply), you should expect to buy a minimum of:
5 bottles of sparkling wine
(20 people x 2 glasses per person = 40 glasses/8 glasses per bottle = 5 bottles)
7 bottles of table wine
(20 people x 2 glasses per person = 40 glasses/6 glasses per bottle = 7 bottles)
But of course there is more to it than that!
Photo courtesy yashima via Flickr/CC