Is this how I calculate my “rent” for a co-op?

Are you trying to compare your costs vs. renting? a couple of suggested tweaks to your formula:
1) instead of counting your entire mortgage, you could count only the interest portion, as the rest goes into principal
2) unless you itemize, you might not be able to even use those tax deductions

Thanks! Just wanted to get a ballpark figure. Yeah, I forgot to deduct principal, which would be around $8,000, which isn't too far off from the $5,000 in deductions (if I can get them, true enough. I itemize every year but this year I may not have made enough to make it worthwhile...)

In theory you should also fold in an "opportunity cost" on your equity.

I am not entirely sure about the opportunity cost of equity. The $$$ is invested in equity of an apartment which is an asset class that does not have the highest return, but an inflation hedge and also not particularly volatile. Could be considered an appropriate investment for more risk averse people.

I did forget about an allowance for improvements/repairs. If you rent, these are covered by the landlord. If you own, you have so pay for plumbing, upgrading finishes, etc.

Thanks for all the feedback! This gives me a ballpark, at least