Free planning tool · 2026

Illinois Estate Tax Calculator

Get a clearer picture of your Illinois estate tax exposure. Enter your figures, explore the assumptions, and take a printable summary into your planning conversation.

Start with an estate value after allowable deductions, but before deducting Illinois estate tax. Use the optional worksheet if you need help organizing the amount.

Help me estimate the amount to enter

Use this worksheet for a straightforward estate. Include each asset once. Blank worksheet fields count as $0. Estimates are only as complete as the information you enter.

This worksheet does not determine ownership, deductibility, valuation discounts, or Illinois QTIP adjustments. If those issues apply, use a professionally prepared Form 700 figure in the main field below.

1. Add includible assets

Home and other real estate

Use the includible ownership share at market value, before mortgages.

Cash and taxable investment accounts

Include trust-owned and jointly owned amounts only to the extent includible.

Retirement accounts

Include applicable IRA, 401(k), and other retirement benefits.

Business and farm interests

Use an estimated includible value; specialized valuation may be needed.

Includible life insurance proceeds

Use the death benefit if includible—not simply the policy cash value.

Other includible property

Include personal property and other interests not counted above.

2. Subtract allowable deductions

Allowable debts and expenses

Count an allowable mortgage or expense once; exclude the Illinois estate tax calculated here.

Qualifying marital deduction

Not every transfer to a spouse or trust qualifies. Confirm eligibility first.

Qualifying charitable deduction

Include only deductible transfers to qualifying recipients.

Do not subtract lifetime gifts here. Enter adjusted taxable gifts separately below. Changing this worksheet does not update the main amount until you select the button.

Illinois tentative taxable estate

For a prepared return, use Form 700, Schedule A or B, line 3. Include required Illinois QTIP adjustments. Do not deduct the $4 million exclusion or the estimated state estate tax from this input.

Adjusted taxable gifts (after 1976)

Use Form 700, Schedule A or B, line 4—not all lifetime gifts and not line 5. Leave $0 only if none. If unknown, confirm your gift-tax records before relying on the estimate.

No email required. The calculation runs in your browser.

A.H.Steinmetz, Ltd. · Illinois estate planning

Illinois estate tax planning estimate

Illinois tentative taxable estate
Adjusted taxable gifts
Estimated Illinois estate tax

What this estimate assumes

Illinois resident; all property has Illinois tax situs; 2026 law. The estate input is after allowable deductions and applicable Illinois QTIP adjustments, but before the Illinois estate tax deduction. The calculator does not determine whether deductions or valuations are legally available.

No out-of-state apportionment, federal estate tax, penalties, or interest is included. Prior gifts can affect tax. A zero estimate does not establish that no return is required. This is general information, not a tax return or individualized legal advice.

Prepare for a conversation

Gather an asset list, ownership details, existing estate-planning documents, and any gift-tax returns. Confirm uncertain values and deductions with your advisers.

Discuss your estate tax exposure: (618) 281-7618
https://steinmetzltd.com/schedule-consultation/

Calculator: https://steinmetzltd.com/illinois-estate-tax-calculator/
Official forms and calculation: https://illinoisattorneygeneral.gov/estate-taxes/

Before you calculate

Two numbers. Important distinctions.

Tentative taxable estate is an estate-tax figure, not simply your net worth or the property passing through probate. The optional worksheet helps organize assets and deductions; a prepared Form 700 is preferable for complex estates.

Adjusted taxable gifts are entered separately. The calculator adds them to the estate figure for the relevant part of the computation. Do not enter the combined total in the gifts field.

Is this estimate right for your situation?

This tool assumes an Illinois resident and all property having Illinois tax situs. It does not apportion tax for property outside Illinois, determine deductions, or calculate QTIP elections. A professional can supply an adjusted input where appropriate.

It estimates Illinois estate tax only, excluding federal tax, generation-skipping tax, penalties, and interest.

The $4 million threshold

The Illinois exclusion is a threshold in an interrelated calculation—not a flat deduction followed by a single tax rate. The state estate-tax deduction affects the computation itself.

A $0 estimate is not a filing determination. Gross estate value plus adjusted taxable gifts can trigger an Illinois return even when deductions eliminate the tax.

See the Attorney General’s instructions and Form 700, Schedules A and B.

Illinois estate tax examples

Each example assumes an Illinois resident, all property with Illinois tax situs, and a tentative taxable estate already adjusted for allowable deductions other than Illinois estate tax. Amounts are rounded to whole dollars.

$4,000,000 estate

Adjusted taxable gifts: $0
Estimated Illinois estate tax: $0

At the exclusion threshold with no adjusted taxable gifts.

$4,100,000 estate

Adjusted taxable gifts: $0
Estimated Illinois estate tax: $28,571

A modest increase above the threshold can create a meaningful tax bill.

$5,000,000 estate

Adjusted taxable gifts: $0
Estimated Illinois estate tax: $285,714

Matches the Attorney General’s published $5 million example.

$3,000,100 estate

Adjusted taxable gifts: $1,000,000
Estimated Illinois estate tax: $29

Prior gifts can produce tax even when the remaining estate is below $4 million.

The $4 million and $5 million examples match the Attorney General’s fact sheet. The prior-gift illustration estimates $29; the fact sheet shows $28 because of differences in iterative rounding. Actual facts can change the result.

Understand your inputs

What belongs in the worksheet?

Think beyond assets passing under a will. Depending on ownership and tax rules, an estate can include retirement benefits, joint property, trust interests, business holdings, and life insurance. Use the includible share of each asset and avoid counting it twice.

Enter real estate before subtracting an allowable mortgage in the deductions section. For life insurance, determine whether the death benefit is includible; a policy’s cash value is not a substitute. Allowable administration expenses, debts, and qualifying marital or charitable transfers may reduce the estate.

The worksheet performs arithmetic only. It does not decide which property is includible or whether a deduction qualifies. Review the IRS Form 706 instructions with your adviser when ownership, beneficiary designations, or deductions are uncertain.

Questions to bring to a planning conversation

Can a married couple simply double the Illinois exclusion?

No automatic portability applies to the unused Illinois exclusion. The first spouse’s estate plan and asset ownership matter. Ask how the plan addresses both deaths, including any appropriate marital and QTIP trust planning. A marital deduction can defer tax without necessarily eliminating exposure at the surviving spouse’s death.

What if I own property in Missouri or another state?

This calculator shows the preliminary amount before apportionment. Illinois Form 700 distinguishes property by tax situs; a bank account’s address alone does not answer the question. Have an adviser apply the state’s situs and apportionment rules, especially for real estate or tangible property elsewhere.

Do I subtract Illinois estate tax before entering my estate?

No. The calculation handles the interrelated state estate-tax deduction. Subtracting the result yourself before entering the figure would count that deduction twice. Use Form 700’s Illinois tentative taxable estate figure when available.

What should I gather before a consultation?

Bring an asset list with approximate values and ownership, your will and trust documents, life insurance details, and any gift-tax returns. Mark uncertain figures rather than treating them as zero. Your printable summary can help organize the conversation.

Sources and calculation method

The estimate uses the former federal state death tax credit calculation and Illinois’s hypothetical federal-tax limitation, accounting for the interrelated state estate-tax deduction. It is checked against published state examples, with small whole-dollar differences possible from iteration and rounding. It is not an official government calculator.

Illinois Attorney General’s official calculator for 2013–2026 decedents
Illinois Form 700 — estate inputs, QTIP adjustments, and apportionment
Illinois estate tax instructions and examples

Explore estate and gift tax planning.