A check always involves a bank while a bill of exchange can involve anyone, including a bank. Checks are payable on demand while a bill of exchange can specify that payment is due on demand or at a specified future date. Bills of exchange generally do not pay interest, making them in essence post-dated checks. They may accrue interest if not paid by a certain date, but that rate must be specified on the instrument. Unlike a check, a bill of exchange is a written document outlining a debtor's indebtedness to a creditor.