The Obamas and Bidens are expected to attend both balls.
Organizers say they will take advantage of every room in the Convention Center to maximize attendance.
"Americans from across the country will be invited to share in the celebration at The Inaugural Ball, a unified celebration for all Americans that will span every Hall in the Convention Center," said Presidential Inaugural Committee spokeswoman Addie Whisenant.
For the military ball, active and reserve military service members will be invited, along with Medal of Honor recipients and wounded warriors. Inaugural planners will work with the Department of Defense and others to distribute the tickets, which are free.
In addition, first lady Michelle Obama and Jill Biden will hold a concert at the Convention Center on Jan. 18, the Saturday before the inauguration, for military spouses and their children. The talent lineup hasn't been announced, but a source says it will feature "popular young artists."