Hi Dave,
Unfortunately - such a thing as an "alimony calculator" for NY does not exist, because alimony is not set by any kind of objective formula in NY. The statute has 14 factors that are applied by a judge (if you are in court) - so it's really anyone's best guess what a court would set as spousal maintenance.
Where maintenance is an issue, you have a great motivation for mediating - because you will both have input into what it will end up as - and you are not subject to completely unknown results set at the whim of a judge. You will make sure you are not left penniless - she will make sure she's not out in the streets - and you will put your heads together and figure out something that is fair and workable for you both.
I can tell you that - as a starting point for the discussion - you and your wife would both want to put together spreadsheets that reflect both of your living expenses - and incomes - and the goal would be for both of you to be able to get through the next couple of years not having to eat cat food.
A general rule of thumb used by the NY courts is that spousal maintenance (not called alimony, in NY) would last for no more than 1/3 to 1/2 the length of the marriage - unless the recipient is permanently disabled. So - this would most likely be some transitional money, to help your wife have a little bit of financial ease, for a short period of time, as she adjusts to the separation and figures out how to become self-supporting.
Best of luck to you both!
Rachel