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 to understand exactly what changed and what it could mean 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 does not owe 1% on the first $2 million and 2% on the dollar above it. The whole transaction is 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 did not exist for you a year ago. 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 is an approximate $122,500 difference in who is responsible for the fee and where it used to fall.
If you're buying, you no longer see this line item on your side of the ledger. That does not make it irrelevant to the negotiation. A seller absorbing a meaningful fee may have less room to move on price than the listing suggests.
Buyers and sellers can agree in the contract to allocate this fee differently. That is a negotiation point, not a given. The state still holds the seller responsible regardless of what the contract says between the parties.
Plan for It Before Closing
Whichever side of the transaction you're on, this is not a fee to discover for the first time at closing. If you're weighing a sale or purchase above $1 million, the number belongs in the conversation before you price a listing or write an offer.
Want to see exactly what this means for your own transaction?
A mansion tax calculator is live on my Tools page. Enter a sale price to see the rate and estimated dollar amount, or reach out and I will run the numbers with you.