What size dog crate should I buy?

Across the reviewers we read, the consensus is to size the crate so your dog can stand, turn around, and lie down comfortably, but no larger. For puppies, verified-purchase reviewers and r/puppy101 threads strongly favor a larger crate with a divider panel so you can expand the usable space as the dog grows rather than buying twice. Manufacturer sizing charts (e.g. MidWest's 36-inch for 41-70 lb dogs and 42-inch for 71-90 lb dogs) are a reasonable starting point.