Try this...

Following is a link to a bitcoin calculator in Excel that I have been improving and maintaining for some time now.  It is based on an original model created by the folks at Bitmain.  The historical data is current as of the last difficulty change.

https://drive.google.com/file/d/0B1DkFD-cfVr4d2NkV2hyWTE2NVk/edit?usp=sharing

PM me with any question or enhancement requests.