Is there a way in calculating the total number of reputation points one gained only on his/her answers? Currently the reputation points for questions and answers are combined total.
To answer the question as the others have, you can use Data Explorer; specifically, this query, which does it by all post types:
select pt.Name , sum(case when v.VoteTypeId = 2 then 10 when v.VoteTypeId = 3 then -2 end) as [Post Reputation] , sum(case when v.VoteTypeId = 2 then 10 when v.VoteTypeId = 3 then -2 when v.VoteTypeId = 1 and pt.Id = 1 then 2 when v.VoteTypeId = 1 and pt.Id = 2 then 15 end) as [Post Reputation, inc. accepts] , sum(case when v.VoteTypeId = 16 then 2 end) as [Approved Edits] from Posts p join Votes v on p.Id = v.PostId join PostTypes pt on p.PostTypeId = pt.Id where p.OwnerUserId = ##UserID## group by pt.Name
It won't give you any information on upvotes since the last update of the Data Explorer database, which is typically weekly.
Since in general it is not possible to exactly calculate rep from any particular posts (see this question), the answer is no. If you don't care about things like the reputation cap and community wiki, then you can get a rough estimate.