Hobbies and Interest both are different.  Hobby is the thing which we use for time passing at our leisure time.  But, Interest is according to the individual choice.  Interest will differ from person to person depends upon their own choice individually.
1 5 1
A hobby, is an activity that one engage himself/herself regularly as leisure time.An "interest" in something can mean different things. It could mean that you have a curiosity about something, an involvement in a crusade, or mission, or infer that a more concentrated effort or financial involvement in something, whether for profit or charity.