I think it's being downvoted because the calculator does take this scenario into account, but the commenter (and you) seem to have not looked at it very hard. I

I think it's being downvoted because the calculator does take this scenario into account, but the commenter (and you) seem to have not looked at it very hard. It clearly recommends that you buy instead of rent in the commenter's (and your) scenario: How Long Do You Plan to Stay: Max this. Investment Rate of Return: Zero this. Because you seem to assume that the renter isn't investing the downpayment, principle payments and any other net savings and won't be able to trade the proceeds for 100% ownership in the home at the end of what would have been the mortgage period. Or set it to -10% (the max negative the calculator allows) if you assume the renter will squander rather than invest the money, with no commensurate happiness return. The result with be buying is better than renting unless you can rent that home at an impossibly low price.