Illinois Estate Tax Calculator (2026): Estimate What the Estate Owes
Figures verified October 17, 2026 against Illinois Attorney General · Update log
Short answer
Yes. For deaths in 2026, Illinois taxes estates over $4,000,000 at up to 16%. Illinois figures the tax with an interrelated calculation on the Attorney General's website, because the Illinois tax is itself deducted from the estate. The executor files Form 700 (filed with the Attorney General) and pays from the estate, due 9 months after the date of death. Federal estate tax applies only above $15 million, so most estates that owe Illinois tax owe nothing federally.
Illinois 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.
Illinois has no inheritance tax; it is the estate that pays. The $4 million exemption is a threshold, not a credit, and the tax is figured with an interrelated calculation because the Illinois tax is itself deducted from the estate.
How the Illinois 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.
Illinois treats its $4,000,000 exemption as a threshold, not a credit. Above it, the tax is the lesser of two amounts: the old federal credit for state death taxes (Table B, applied to the estate minus $60,000) and 40% of the amount over $4,000,000. Because the Illinois tax is itself deductible, the estate used in both is the estate minus the Illinois tax, which is why the Attorney General publishes a calculator. For an estate a little over the threshold, the 40% limit decides the tax.
This is an approximation. It solves the same interrelated equation as the Attorney General's calculator and reproduces the examples in the AG's 2026 fact sheet, but it assumes all property is in Illinois. Use the AG's calculator for the figure on the return. See the Illinois Attorney General estate tax calculator.
Table B rates, shown in estate dollars (before the limit)
| Taxable estate over | Up to | Rate on that slice |
|---|---|---|
| $100,000 | $150,000 | 0.8% |
| $150,000 | $200,000 | 1.6% |
| $200,000 | $300,000 | 2.4% |
| $300,000 | $500,000 | 3.2% |
| $500,000 | $700,000 | 4% |
| $700,000 | $900,000 | 4.8% |
| $900,000 | $1,100,000 | 5.6% |
| $1,100,000 | $1,600,000 | 6.4% |
| $1,600,000 | $2,100,000 | 7.2% |
| $2,100,000 | $2,600,000 | 8% |
| $2,600,000 | $3,100,000 | 8.8% |
| $3,100,000 | $3,600,000 | 9.6% |
| $3,600,000 | $4,100,000 | 10.4% |
| $4,100,000 | $5,100,000 | 11.2% |
| $5,100,000 | $6,100,000 | 12% |
| $6,100,000 | $7,100,000 | 12.8% |
| $7,100,000 | $8,100,000 | 13.6% |
| $8,100,000 | $9,100,000 | 14.4% |
| $9,100,000 | $10,100,000 | 15.2% |
| $10,100,000 | and above | 16% |
Worked example: a $5.2 million Illinois estate
A Naperville widower dies with a $1.2 million house, $2.1 million of brokerage accounts, a $1.4 million IRA and a $500,000 life insurance policy he owned. Debts are $50,000 and costs $150,000, leaving a $5,000,000 taxable estate, the same figure as the Attorney General's own example.
Step by step
| Everything the person owned (gross estate) | $5,200,000 |
| Debts and mortgages | − $50,000 |
| Funeral and administration costs | − $150,000 |
| Taxable estate | $5,000,000 |
| State exemption (2026 deaths) | $4,000,000 |
| Estate after deducting the Illinois tax itself | $4,714,286 |
| Table B amount on that, minus $60,000 | $359,600 |
| Limit: 40% of the amount over the exemption | $285,714 |
| Estimated state estate tax | $285,714 |
Bracket by bracket
Illinois rates applied to the estate after deducting the Illinois tax itself, minus $60,000 (the Table B rates). Amounts are shown in estate dollars.
| Slice of the estate | Amount | Rate | Tax |
|---|---|---|---|
| $100,000 to $150,000 | $50,000 | 0.8% | $400 |
| $150,000 to $200,000 | $50,000 | 1.6% | $800 |
| $200,000 to $300,000 | $100,000 | 2.4% | $2,400 |
| $300,000 to $500,000 | $200,000 | 3.2% | $6,400 |
| $500,000 to $700,000 | $200,000 | 4% | $8,000 |
| $700,000 to $900,000 | $200,000 | 4.8% | $9,600 |
| $900,000 to $1,100,000 | $200,000 | 5.6% | $11,200 |
| $1,100,000 to $1,600,000 | $500,000 | 6.4% | $32,000 |
| $1,600,000 to $2,100,000 | $500,000 | 7.2% | $36,000 |
| $2,100,000 to $2,600,000 | $500,000 | 8% | $40,000 |
| $2,600,000 to $3,100,000 | $500,000 | 8.8% | $44,000 |
| $3,100,000 to $3,600,000 | $500,000 | 9.6% | $48,000 |
| $3,600,000 to $4,100,000 | $500,000 | 10.4% | $52,000 |
| $4,100,000 to $4,714,286 | $614,286 | 11.2% | $68,800 |
| Total from the brackets | $359,600 | ||
The bracket total differs from the tax because of the credit or limit shown in the steps above.
Result: Illinois estate tax of $285,714, or 5.7% of the $5,000,000 taxable estate. No federal estate tax, because the estate is under $15 million. Illinois requires Form 700 when the gross estate plus adjusted taxable gifts is over $4,000,000, whether or not a federal return is due.
Ways the number can change
- Property outside Illinois. Illinois works out the tax as if everything were in Illinois, then multiplies it by the share of the estate located in Illinois. In the Attorney General's example, a $5,000,000 estate with half in Florida owes $142,857 instead of $285,714, even though Florida has no estate tax.
- Lifetime gifts. Adjusted taxable gifts count toward the $4,000,000 threshold and enter the calculation. The Attorney General's example: a $3,000,100 estate with $1,000,000 of earlier gifts owes $28.
- An Illinois-only QTIP election. Property left in trust for a spouse can be deferred with a separate Illinois QTIP election on a timely Illinois return. The Attorney General's example: a $13,610,000 estate with a $9,610,000 Illinois QTIP election owes no Illinois tax.
- No portability. The unused federal exemption that passes to a surviving spouse does not apply to the Illinois tax. Each spouse's estate has its own $4,000,000 threshold.
- 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 Illinois rate on that slice.
What the executor files, and when
- Illinois Form 700 (filed with the Attorney General): due 9 months after the date of death. Illinois requires Form 700 when the gross estate plus adjusted taxable gifts is over $4,000,000, whether or not a federal return is due.
- File Form 700 with the Illinois Attorney General (not the Department of Revenue). Pay the Illinois State Treasurer. A Form 700 is required whenever the estate plus adjusted taxable gifts is over $4,000,000, even if no federal return is due. Illinois Attorney General.
- 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 Illinois estate tax return
Tell us a little about the estate and a CPA or Enrolled Agent who prepares Illinois estate tax returns will reply with a fixed price. Free, and no obligation.
Frequently asked questions
How much is Illinois estate tax on a $5 million estate?
About $286,000 on a $5,000,000 taxable estate, and about $456,000 on $6,000,000. That assumes a Illinois resident with everything in Illinois 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.
Who files the Illinois estate tax return, and when is it due?
The executor (personal representative) files Form 700 (filed with the Attorney General), due 9 months after the date of death. File Form 700 with the Illinois Attorney General (not the Department of Revenue). Pay the Illinois State Treasurer. A Form 700 is required whenever the estate plus adjusted taxable gifts is over $4,000,000, even if no federal return is due.
Does the estate have to file if it owes no Illinois tax?
Illinois requires Form 700 when the gross estate plus adjusted taxable gifts is over $4,000,000, whether or not a federal return is due.
Is there an Illinois inheritance tax?
No. Illinois has an estate tax, paid by the estate before heirs are paid, not an inheritance tax on what each heir receives. Heirs owe no Illinois tax on their inheritance.
Is this the same as the Illinois Attorney General's estate tax calculator?
It solves the same interrelated equation and reproduces the examples in the Attorney General's 2026 fact sheet, such as $285,714 on a $5,000,000 estate. The AG's calculator is the one to use for the return, especially if any property is outside Illinois.
Where is the Illinois estate tax paid?
Form 700 is filed with the Illinois Attorney General, but the tax, interest and penalties are paid to the Illinois State Treasurer. Both are due 9 months after death.
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. Illinois's exemption is $4,000,000, so many estates owe Illinois tax and no federal tax. The Illinois tax paid is deductible on the federal return.
How accurate is this calculator?
It uses Illinois's official rate table for 2026 deaths, with an approximation of the official method that is explained on this page. It assumes the person lived in Illinois 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
- 1.Illinois Attorney General: 2026 estate tax fact sheet (examples, filing, QTIP)illinoisattorneygeneral.gov
- 2.Illinois Attorney General: estate taxes and official calculatorillinoisattorneygeneral.gov
- 3.Illinois Attorney Generalillinoisattorneygeneral.gov
- 4.IRS: Estate Taxirs.gov
- 5.IRS: Instructions for Form 706irs.gov
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.