Do you stop eating bread once Seder starts or beginning of the morning of Seder day? Not sure about this
2 Answers
The precise time depends on exactly where you are. For example, the times for Glencoe Illinois for tomorrow are (courtesy of the chabad.org web site)
Finish Eating Chametz before: 10:38 AM
Sell and Burn Chametz before: 11:44 AM
go to the site and change the location to your zip code for relevant times.
From Biblical law, you stop eating bread products at mid-day preceding the seder. Rabbinical law extends the prohibition an extra hour before that to distance from the Biblical prohibition, and a further hour due to the possibility of confusion.