I will have studied << future perfect tense It is used to tell a complete activity in the future before another activity happen example: your parents will come at night and you have much time to study before they come. So when they arrive, you are no longer studying. "I will have studied by the time they arrive." I will have been studying << future perfect continuous tense It is used to tell that something going on from the past and still continue in the future example: you were accepted in college in 2013. 2013 was your 1st year and this year is your 2nd year. you can say "I will have been studying here for 3 years next year" hope it helps

Ok, I hope this makes sense. ;) Basically, "to have studied" and "to have been studying" mean the same thing. The first is active, the second is passive. The first is past, the second is present. And, most importantly, these verb phrases would decide the tense of the rest of the sentence. Each phrase is called a participle. The "-ed" denotes past; the "-ing" denotes present. So, "have studied" is past participle, and "have been studying" is present participle. "I have studied longer than any other classmate." "I will have been studying longer than any other classmate." "I have studied every night." "I will have been studying for 3 hours when you arrive."