Connecticut Estate Tax Calculator (2026): Estimate What the Estate Owes
Figures verified October 17, 2026 against Connecticut Department of Revenue Services · Update log
Short answer
Yes. For deaths in 2026, Connecticut taxes estates over $15,000,000 at 12% flat on the amount over the exemption. Connecticut's exemption equals the federal one, and it is the only state that also has a gift tax, so lifetime gifts since 2005 are added back. The executor files CT-706/709 and pays from the estate, due 6 months after the date of death. Because the Connecticut exemption equals the federal $15 million, an estate that owes Connecticut tax usually owes federal estate tax too.
Connecticut estate tax calculator
Enter values at the date of death. Rough numbers are fine; type 450000, 450k or 2.5m. Leave anything that does not apply blank.
How the Connecticut estate tax is calculated
The starting point is the taxable estate: everything the person owned at death (the gross estate), minus debts and mortgages, funeral and administration costs, and what passes to a surviving spouse or to charity. The house, bank and brokerage accounts, retirement accounts, business interests and life insurance the person owned all count, including accounts that pass straight to a named beneficiary.
Connecticut charges a flat 12% on the part of the taxable estate over $15,000,000, with gifts made since 2005 added back first.
Connecticut rates for 2026 deaths
| Taxable estate over | Up to | Rate on that slice |
|---|---|---|
| $15,000,000 | and above | 12% |
Worked example: a $18 million Connecticut estate
A widow dies in Greenwich with a $3 million house, an $11 million brokerage account, a $3 million IRA and a $1 million life insurance policy she owned. Debts are $200,000 and costs $300,000. In 2019 she gave her son $1,000,000 above the annual exclusion.
Step by step
| Everything the person owned (gross estate) | $18,000,000 |
| Debts and mortgages | − $200,000 |
| Funeral and administration costs | − $300,000 |
| Taxable estate | $17,500,000 |
| Lifetime gifts added back | + $1,000,000 |
| Estate taxed by the state | $18,500,000 |
| State exemption (2026 deaths) | $15,000,000 |
| Estimated state estate tax | $420,000 |
Bracket by bracket
Connecticut rates applied to the amount over the exemption. Amounts are shown in estate dollars.
| Slice of the estate | Amount | Rate | Tax |
|---|---|---|---|
| $15,000,000 to $18,500,000 | $3,500,000 | 12% | $420,000 |
| Total from the brackets | $420,000 | ||
Result: Connecticut estate tax of $420,000, or 2.3% of the $18,500,000 taxable estate (with gifts added back). Federal estate tax of roughly $832,000 is also due (40% of the amount over $15 million, after deducting the Connecticut tax). Every Connecticut estate files something: CT-706/709 with DRS above $15,000,000, or CT-706 NT with the Probate Court at or below it.
Ways the number can change
- Lifetime gifts since 2005. Every Connecticut taxable gift made since January 1, 2005 is added to the estate. Connecticut gift tax already paid is credited against the estate tax, and the combined gift and estate tax is capped at $15 million.
- A Connecticut QTIP election. A Connecticut QTIP election for property left in trust for a spouse is made on Form CT-706/709, not on the CT-706 NT that smaller estates file with the Probate Court.
- Real estate in another state. If the person owned a house or land in another state, Connecticut's figure can come down and the other state may want its own return. Most estate-tax states tax a resident's out-of-state real estate only in part or not at all, so give the preparer the addresses and values.
- The federal figure moves Connecticut's. Because the Connecticut exemption is the federal basic exclusion amount, it changes each year with the federal one.
- Values at the date of death. The return uses appraised fair market values on the date of death. A house or business valued differently from your estimate moves the tax, at the Connecticut rate on that slice.
What the executor files, and when
- Connecticut CT-706/709: due 6 months after the date of death. Every Connecticut estate files something: CT-706/709 with DRS above $15,000,000, or CT-706 NT with the Probate Court at or below it.
- Estates over the exemption file Form CT-706/709 with the Department of Revenue Services. Estates at or below it file Form CT-706 NT with the Probate Court. An extension to file is requested on Form CT-706/709 EXT. Connecticut Department of Revenue Services.
- Federal Form 706: only if the estate is over $15 million, or to elect portability for a surviving spouse. Due 9 months after the date of death (an automatic 6-month extension to file is available on Form 4768).
Optional: get help filing
Get a flat-fee quote to file the Connecticut estate tax return
Tell us a little about the estate and a CPA or Enrolled Agent who prepares Connecticut CT-706 returns will reply with a fixed price. Free, and no obligation.
Frequently asked questions
How much is Connecticut estate tax on a $17.5 million estate?
About $300,000 on a $17,500,000 taxable estate, and about $600,000 on $20,000,000. That assumes a Connecticut resident with everything in Connecticut and no lifetime gifts. The taxable estate is what is left after debts, funeral and administration costs, and what goes to a spouse or charity.
Does Connecticut have an inheritance tax?
No. Connecticut has an estate tax, paid out of the estate before heirs receive their shares, and no inheritance tax. Heirs do not pay Connecticut tax on what they receive.
Who files the Connecticut estate tax return, and when is it due?
The executor (personal representative) files CT-706/709, due 6 months after the date of death. Estates over the exemption file Form CT-706/709 with the Department of Revenue Services. Estates at or below it file Form CT-706 NT with the Probate Court. An extension to file is requested on Form CT-706/709 EXT.
Does the estate have to file if it owes no Connecticut tax?
Every Connecticut estate files something: CT-706/709 with DRS above $15,000,000, or CT-706 NT with the Probate Court at or below it.
Does a small Connecticut estate have to file anything?
Yes. Estates at or below the $15,000,000 exemption file Form CT-706 NT with the Probate Court for the district, not with DRS. Larger estates file Form CT-706/709 with DRS within 6 months of death.
How are lifetime gifts counted in Connecticut?
The Connecticut taxable estate adds all Connecticut taxable gifts made since January 1, 2005 (gifts above the annual exclusion), plus any Connecticut gift tax paid on gifts in the 3 years before death. Gift tax already paid is credited against the estate tax.
Are life insurance and retirement accounts part of the estate?
Yes. Retirement accounts count at their full balance, and life insurance counts if the person owned the policy or it paid the estate, even when a named beneficiary receives the money. Income tax on withdrawals from an inherited IRA is separate and is paid by the heir.
Will the estate owe federal estate tax as well?
Only if it is over $15,000,000 for 2026 deaths. Connecticut's exemption is the same as the federal one, so a taxable Connecticut estate usually owes both. The Connecticut tax paid is deductible on the federal return.
How accurate is this calculator?
It uses Connecticut's official rate table for 2026 deaths. It assumes the person lived in Connecticut with everything located there, and it uses the values you enter. The real return uses appraised values at the date of death and can include items it does not model, such as property in other states, state-only elections and credits for tax paid to other states.
Sources
This information is provided for educational purposes only and should not be considered legal or tax advice. Consult a qualified tax professional for guidance specific to your situation.