What happens to a Westfield seller's proceeds when a $2,000 difference in sale price triggers a $20,000 difference in taxes owed?
That question sounds like a rounding error until you look at how New Jersey rewrote its so-called mansion tax last year. The rule used to apply mostly to trophy properties and mostly to buyers. As of today, it applies to sellers, it applies across a graduated scale instead of a flat rate, and in Westfield, where the median sale price has been running well north of $1.3 million through 2026, it applies to most of the town, not the exception.
If you're planning to list a Westfield home anytime soon, this is the closing cost conversation to have before you sign anything, not after an offer lands.
The Fee Everyone Remembers Wrong
New Jersey has had a supplemental Realty Transfer Fee on residential sales over $1,000,000 since 2004. Most people who've bought or sold in that range over the past two decades know it by its nickname, the mansion tax, and most of them remember it as a flat 1% charge that came out of the buyer's pocket at closing. That memory was accurate for twenty-one years. The base Realty Transfer Fee itself, the smaller graduated fee that applies to every New Jersey home sale regardless of price, has always been the seller's cost and has been in place since 1968. The mansion tax add-on was the exception, and it belonged to the buyer.
That arrangement ended on July 10, 2025.
What Changed, and Why It Matters More Here Than Almost Anywhere Else in the County
On June 30, 2025, Governor Murphy signed legislation tied to the state's fiscal year 2026 budget that rewrote both pieces of this fee. The flat 1% mansion tax is gone. In its place is a graduated fee that climbs with the sale price, and it now falls entirely on the seller.
| Sale Price | Rate on Entire Sale Price |
|---|---|
| $1,000,000 to $2,000,000 | 1% |
| $2,000,000 to $2,500,000 | 2% |
| $2,500,000 to $3,000,000 | 2.5% |
| $3,000,000 to $3,500,000 | 3% |
| Above $3,500,000 | 3.5% |
Two details in that table change the math for anyone selling in this range. The rate applies to the entire sale price once you cross a threshold, not just the portion above it. And the obligation to pay now sits with the seller, on top of the base Realty Transfer Fee sellers were already covering.
There was a brief window where the old rules still applied. Contracts fully executed before July 10, 2025 could close under the prior 1% buyer-paid structure, provided the deed was recorded by November 15, 2025, with a refund process available for anyone caught in between.
That window closed in November 2025. Every Westfield listing that goes under contract today operates entirely under the new rule. There is no version of this transaction left where the old math applies.
Why This Isn't a Luxury-Home Story in Westfield
In a lot of New Jersey towns, a $1 million threshold still functions the way it was designed to function twenty years ago, as a marker for the top slice of the market. Westfield isn't one of those towns anymore.
Multiple data sources tracking Westfield sales through 2026 put the town's median sale price somewhere in the $1.3 million to $1.4 million range, with figures from this summer showing the median above $1.34 million, up more than 8 percent from a year earlier. That's not the price of the nicest house on the block. That's the midpoint of the entire market, the number that means half of Westfield's sales are landing above it.
Renovated colonials near downtown have listed recently in the $1.9 million to $2.2 million range, which puts a meaningful slice of Westfield's active inventory not just above the $1 million line but within reach of the $2 million line, where the rate itself steps up.
Put those two facts together and the mansion tax stops being an edge case for Westfield sellers. It's the baseline. A seller listing a typical Westfield home this year isn't asking whether this fee applies to them. They're already inside it.
The Cliff Nobody Warns You About
Here's where the graduated structure creates a genuinely strange incentive, and it's the part sellers most need to understand before they price a home.
Because the fee applies to the full sale price once you cross a threshold, not the amount above it, a small difference in final sale price can produce a disproportionate difference in what a seller owes.
Take two nearly identical Westfield homes. One sells for $995,000. Because it lands under the $1,000,000 threshold, the seller owes no supplemental fee at all. A home two blocks over sells for $1,015,000, roughly 2% more. That seller doesn't just owe a little more tax on the difference. They owe 1% of the entire $1,015,000, or roughly $10,150, a cost the first seller never had to think about.
The same cliff shows up again at $2,000,000. A home selling for $1,999,000 owes 1% of the full price, about $19,990. A home selling for $2,001,000, just $2,000 more, jumps to the 2% tier applied to the entire amount, about $40,020. A $2,000 difference in what the buyer offers turns into roughly a $20,000 difference in what the seller nets.
This is the detail that makes pricing strategy near these lines a real conversation, not an afterthought. It's also exactly the kind of number that needs to be built into a seller's net proceeds estimate before an offer arrives, not calculated for the first time at the closing table.
What Actually Reduces the Bill
New Jersey does carve out some exceptions, and it's worth knowing which ones might apply before you assume the full rate is unavoidable.
- Sellers who are 62 or older, blind, or permanently disabled can claim a partial exemption on the first $150,000 of the sale price, but that carve-out applies to the standard Realty Transfer Fee. State guidance is explicit that the Graduated Percent Fee itself carries no senior, disability, or veteran discount, so this exemption trims the smaller fee, not the mansion tax portion.
- Transfers between spouses are exempt from the fee entirely, as are transfers recorded within 90 days of a divorce decree.
- Transfers to or from a government body or a qualified nonprofit organization are exempt.
- Transfers from an estate to a beneficiary or heir under a will or through intestacy are generally exempt.
- Deeds with nominal consideration of $100 or less are exempt, as are certain vacant land and qualified farmland transfers.
None of these apply automatically. Every sale over $1,000,000 requires an Affidavit of Consideration for the Graduated Percent Fee to be attached to the deed at recording, whether or not an exemption applies, and whether an exemption fits your situation is a question for a real estate attorney reviewing your specific contract and title, not something to assume from a checklist.
Before You Sign a Listing Agreement
If you're weighing a sale in the next year, the practical move is simple. Have your net proceeds conversation include this fee from the start, not as a surprise line item at closing. Ask specifically where your expected sale price falls relative to the $1 million and $2 million lines, since a small shift in either direction changes the math meaningfully. And if your situation might touch one of the exemptions above, raise it with your attorney early enough that it can actually be documented at recording.
Frequently Asked Questions
Does this apply if I signed my contract before July 2025? The relief period for contracts executed before July 10, 2025 required the deed to be recorded by November 15, 2025 to use the old rate. That window is closed. Any contract signed today falls under the new seller-paid graduated fee with no exception.
Is this the same as my property tax bill? No. This is a one-time fee paid at closing when the deed is recorded, calculated as a percentage of your sale price. It has nothing to do with your annual property tax assessment.
Can my buyer agree to cover part of it anyway? The legal obligation to pay sits with the seller under the new law, but who actually covers a cost at closing can still be negotiated between the parties in the purchase contract. That's a conversation for your attorney to structure correctly, not something to assume by default.
Selling in a market where the median price itself now sits inside a tax bracket most sellers didn't expect to touch is exactly the kind of moment where a second opinion on your numbers pays for itself. If you're weighing a sale in Westfield and want a clear-eyed look at what your home might net after every cost, including this one, Jayne Bernstein can walk through the real math with you. Request your home valuation and start the conversation before you set a price, not after.
