I spent 30 years on Wall Street making sure deals were set up correctly from the get-go — the trade capture, the calculations, the monies. Old habits die hard: when New Jersey rewrote the "Mansion Tax" rules, I wanted my clients just as well versed, so they'd know exactly what it means for their bottom line.
What It Is
The "Mansion Tax" isn't really its own tax. It's a supplemental fee tacked onto New Jersey's Realty Transfer Fee, triggered any time a residential sale exceeds $1 million. It's been on the books since 2004.
Who Used to Pay It
For twenty-one years, the buyer paid it. Flat 1% of the sale price, due at closing, no sliding scale. If you closed at $1.2 million, you wrote a check for $12,000. Simple, if not exactly painless.
What Changed, and When
On June 30, 2025, Governor Murphy signed it into a different tax altogether. As of July 10, 2025, two things flipped at once: the seller pays it now, not the buyer, and it's no longer a flat 1%. It's tiered, and it climbs fast.
One detail that catches people off guard: the rate applies to the entire sale price, not just the amount over the threshold. A sale at $2,000,001 doesn't owe 1% on the first $2 million and 2% on the dollar above it — the whole transaction gets taxed at 2%. That makes the exact number you settle on more consequential than it used to be.
Why It Matters Right Now
If you're selling above $1 million in this market, this is a real closing cost that simply didn't exist for you a year ago — and it belongs in your planning from the day you decide to list, not as a surprise on the settlement sheet. On a $3.5 million sale, that's an approximate $122,500 difference in who's responsible for it, and where it used to fall.
If you're buying, you no longer see this line item on your side of the ledger — but don't assume it's irrelevant to your negotiation. A seller who's now absorbing a meaningful fee they didn't budget for a year ago may have less room to move on price than the listing suggests.
Buyers and sellers can privately agree in the contract to allocate this fee differently — that's a negotiation point, not a given — but the state holds the seller responsible regardless of what the contract says between the parties.
The Bottom Line
Whichever side of the transaction you're on, this isn't a fee to discover for the first time at closing. If you're weighing a sale or a purchase above the $1 million mark anywhere in Bergen County or the Hudson River towns, this is exactly the kind of number that belongs in the conversation before you price a listing or write an offer — not after.
Want to see exactly what this means for your own transaction?
A mansion tax calculator built for exactly this is live on my Tools page — plug in a sale price and see the exact rate and dollar amount, or reach out and I'll run the numbers for you directly.