alt Hacker NewsAzure provides their own "Total Cost of Ownership" calculator for this purpose [0]. Notably, this makes you estimate peripheral costs such as cost of having a server administrator, electricity, etc.
[0] - https://azure-int.microsoft.com/en-us/pricing/tco/calculator...
I plugged in our own numbers (60 servers we own in a data centre we rent) and Microsoft thinks this costs us an order of magnitude more than it does.
Their "assumption" for hardware purchase prices seems way off compared to what we buy from Dell or HP.
It's interesting that the "IT labour" cost they estimate is $140k for DIY, and $120k for Azure.
Their saving is 5 times more than what we spend...