Indexes created in a wrong place

I have some indexes created in a wrong tablespace so I have to rebuild them in the correct one.
I am afraid I do not have enough space in the destiny to aloccate all indexes. how can I check the total size used for all of Indexes in the origin and if I have space in the new place to put them ??

Total rows *(rowid lenght+column length) =Index size

dba_segments will give u the details.