As each book is unique, the cost of drafting an index cannot be automatically determined. Before indexing your book I will provide you with a quote for your book that will take a number of factors into consideration, such as the length of the book (without bibliography), the type of index (standard back of book or embedded into a Word manuscript), the discipline/subject matter, number of tables and figures, layout and amount of non-english language used.
You may be searching for an indexer well in advance of when your book has been typeset so I use a word count before bibliography to estimate the cost.
Once the indexing process has begun, last minute changes that affect pagination of final proofs might incur additional costs and/or delay the project. These are billed out at an hourly rate.