Index rebuilding in SQL

When index are rebuild that means the old indexes on the table are dropped and new indexes on the table are created. Due to the creation of the indexes on the table all the data is organised in the leaf level (cluster index) and organised simultaneously. Thus maximum the number of rows in your table , maximum will be the page count and maximum will be the time taken in rebuilding the index. Indexing is nothing but ordering of pages, thus it depends on page count