When it comes to corn on the cob, the general rule of thumb is about one ear per person. However, depending on the size and type of corn, this can vary.  For instance, baby corn, which are smaller ears of corn, will require two or three per person. On the other hand, large ears may only need one ear per person.  Additionally, if you're having a more relaxed gathering with lots of side dishes and appetizers available for snacking, you may want to adjust the portion size accordingly.