I've never actually thought about needing to wait to sleep after eating and always just have dinner at around 8:00 PM and then I'm usually in bed around 10:00 PM to 11:00 PM.
That makes it 2 to 3 hours after dinner that I go to bed and it has never been a problem for me.
However from researching online after reading this question it's recommended to wait at least 3 hours after eating before going to bed which allows time for digestion to occur and the contents of your stomach to move into your small intestine.
However sometimes I've eaten and within 20 to 30 minutes went to sleep and nothing bad has happened but most people do have their dinner at least a few hours before bed.