In Cass wrote:
Half and half is cream for use in coffee and some cooking, less butter
fat than whipping cream.

Heavy cream,
Contains not less than 36 percent milkfat. *

Half-and-half
Contains not less than 10.5 percent but less than 18 percent milkfat.

Ah now that makes sense. Just to clarify, I use full cream milk, not
cream.