estimating construction costs in the Indianapolis area

[Michael Mastantuono]

Is anyone using cost estimating books or software to estimate construction costs on their flips? 

I need it for the rehab budget to supply to the lender.

Or, are you mainly just going off of bids from contractors?

I'd also like to have a way to budget different scenarios like adding a bathroom, or finishing an attic, or adding a garage. 

Thanks.