It depends. There are 2 “standard” sizes of corny keg. Most of the reconditioned ones are shorter and fatter, and most of the brand new ones are taller and thinner.
I can fit 3 reconditioned cornies plus a 10L minikeg in mine, but I reckon if I’d splashed for the brand new kegs I would have got 4 in there. Mine is an Indesit if that’s any help.