You can get the time difference between two dates in almost any technology be it c#, sql server, vb.net, oracle and you can display that in comparision to the current date time with stored date and time..
DateTime startTime = Convert.ToDateTime("06/05/2026");
DateTime endTime = DateTime.Now;
TimeSpan t= endTime.Subtract ( startTime );
Here t contains all the info like t.Days gives number of days, t.Hours gives number of hours, etc..