Coursera I was a Coursera student myself and I was confused by difference between Due Date and Hard Deadline. The difference between due date and hard deadline depends on the course and how that particular instructor is handling the situation. The possibilities are

  1. Submit before the due date with no penalty.
  2. Submit after the due date but before the hard date with no penalty
  3. Submit after the due date but before the hard date with penalties for either each day or a fixed percentage.
  4. Use late days after the due date but before the hard deadline to submit without penalties.
  5. You just cannot submit after the hard deadline even if you have enough late days with you.