This page contains RAID calculators, IOPS calculators and other estimatior tools to use for raid disks and disk arrays. If you know of other calculators, please leave a comment and I’ll list it here. Thanks!
Update: I have an Excel workbook “cheat sheet” that I use to do quick calculation
RAID, IOPS, MBps Excel Cheat Sheet
Great resource for calculating IOPs from a given RAID configuration and also calculating needed disks for average IOPs.