Mayor-elect Zohran Mamdani’s fanciful promises of free stuff met with a cold dose of reality last week.

Mayor Eric Adams’ new financial plan leaves his successor short by as much as $8 billion, Citizens Budget Commission analysts report — and that’s not counting the new cash needed for any fresh freebies.

Or for Washington’s expected rollbacks in federal aid to the city.

To close the $8 billion-plus gap, Mamdani will have to find steep savings in the current budget.

Even if Albany (recklessly) passes both major tax hikes the mayor-elect has called for — on personal income and corporations — and lets him use the entire $9 billion it’s expected to bring in (rather than using some of the statewide tax hikes for statewide spending), he’s still unlikely to have enough to make ends meet without cutting, let alone for new programs.

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Not to mention how such tax hikes would push more than a few high earners and corporations to flee New York — leaving the new revenue far short of what’s hoped for.

So where on Earth will Mamdani find the dough to pay for his promises — i.e., free buses, child care, housing?

His bus idea alone would run nearly $1 billion; child care, another $6 billion — while some versions of his housing plan would require tens of billions.

Does the soon-to-be-Hizzoner think dollars will fall from the sky?

Nor can he count on the state to rescue him.

Yes, Gov. Kathy Hochul may go along with items she’d previously pooh-poohed, from free buses to some tax hikes.

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Yet the state also faces future-year budget gaps, and will likely see cuts in federal aid — to the tune of $8 billion a year, mostly for food stamps and Medicaid.

Don’t think the city’s fiscal picture gets brighter down the road: Adams’ $12 billion cumulative hole through 2029 may actually grow, since his budgets, per the CBC, underestimate spending by about $4 billion.

Perhaps Mamdani has some magical fairy dust stashed away.

But if not, his supporters are in for some major disappointment.