How to use the calculator
- Go to the home page and search any LI address or paste a Zillow URL
- Click “Buy mode” and enter the asking price
- The result page shows: the seller’s current bill, your projected first-year bill, monthly cost, and how exemptions break down
We pull live data from the NY State assessment roll — the same data the County uses to bill the property.
What changes at closing
- STAR exemption removed — Typical $300-$700/yr added to your bill. Register your own STAR immediately at tax.ny.gov/star.
- Enhanced STAR removed (if seller was 65+) — Typical $600-$1,500/yr added. You qualify if you’re 65+ with income under $110,750.
- Senior Citizens exemption removed (if seller qualified) — Up to 50% of property tax bill added. Requires age 65+ and income typically under $58,400.
- Alternative Veterans exemption removed (if seller is a veteran) — 15–25% added back. You can apply if you’re an eligible veteran with appropriate discharge documentation.
- Volunteer Firefighter exemption removed — Varies by town, typically 10% of assessed value added back.
- Assessment may be reset — Most LI towns do NOT reassess on sale — Long Island is unusual in this. Your assessment stays at the prior year’s value.
What to budget for as a buyer
A defensible rule of thumb for new LI homeowners:
- Assume the seller’s bill + 10–25% for the first year (loss of seller exemptions, partial-year of your own STAR)
- Register STAR within 30 days of closing — recovers $300-$700/yr
- File a grievance the first available cycle — Nassau by March 31, Suffolk by third Tuesday of May. Most successful grievances recover 5–15% of assessed value.
The combined effect: STAR credit + grievance + any veteran/senior exemptions can bring your bill to within 5–10% of the seller’s within 18 months.
Common buyer questions
The listing shows $8,500/yr in taxes. What’s my real number?
Plug the address into our calculator. If the property has STAR, Senior, Veteran, or other exemptions, those will drop off at closing. Your real bill is likely 10–30% higher in the first year before you register your own STAR.
Does my mortgage rate care about my exemptions?
Yes. Mortgage lenders calculate your debt-to-income (DTI) ratio using the full property tax bill including exemptions you don’t yet qualify for. Some lenders will use the seller’s bill if it’s in escrow. If you’re borderline on DTI, ask your loan officer to use the post-exemption-loss number.
Can I negotiate the seller covering my first year’s STAR loss?
Rare but happens. More common: ask for a credit at closing covering the difference between the seller’s bill and your projected first-year bill. Your buyer’s agent should run the numbers.
My new construction home has no tax history. How do I project?
New construction is assessed once the certificate of occupancy is issued. Until then, your bill is based on the land assessment only. Once assessed, the bill jumps significantly. Plan for the first full year to land at roughly 1.5–2.5% of purchase price for typical LI homes.
Estimate your exact property tax bill
Enter any Long Island address to see the median bill for the district, your projected bill if you bought today, and how exemptions roll off after a sale.
Get one email when LI tax rules change
Grievance deadlines, STAR limit updates, new exemption laws. One short email, only when something actionable happens. Unsubscribe in one click.
Sources and citations
- NY Tax & Finance — STAR resource center tax.ny.gov
- NY State Open Data — Property Assessment Data data.ny.gov
Last verified May 11, 2026. Tax rules change; we re-check every page each quarter.
Educational content and estimates only, not legal, tax or financial advice. Verify with your county or town receiver, an attorney or a CPA before making financial decisions.