From the MB web site:
5.5-inch - 1 1/4 quarts, Weight:3 lbs. 9 oz.
6.25-inch - 1 14/16 quarts, Weight:4 lbs. 12 oz
7.1-inch - 2 5/8 quarts
7.9-inch- 3 3/4 quarts, , Weight:6 lbs. 9 oz.
I own many Bourgeat copper pieces and they are a lifetime investment. I think they are the best available anywhere at any price. They are quite substantial (check out the weights) and not for the weak-wristed! Their conductivity is awesome and the stainless interior is virtually non-stick. I was lucky enough to purchase mine before the price of 'precious metals' went crazy....
Expensive? Yes. But , if you can afford it, you will NOT be disappointed.