Illinois Estate Tax Calculator

2026 law · reviewed September 3, 2026

Estimates the estate tax Illinois and the federal government would charge on what you leave behind. About

In plain words. An estate is everything a person owns when they die: the house, the accounts, the life insurance. Illinois taxes estates above four million dollars, and the federal government taxes them above a much higher line. This tool takes the size of an estate and tells you how much each government would take, for one person or for a married couple.

Why it matters. If your estate is anywhere near the Illinois line, the difference between planning and not planning can be a six-figure check. Knowing which side of the line you are on is the first step, and the number to bring to an estate attorney.

An example. A single person with a six-million-dollar estate would owe Illinois about $456,000 and the federal government nothing, because six million is under the federal line. The Illinois tax is the whole bill.

Where it stops. It does not value your estate for you, and it does not apply deductions, charitable gifts, or credits. If you own property in another state, or a trust already holds some of your assets, the real answer needs an attorney's return. Everything it leaves out.

Taxable estate (what is left after debts, expenses, and anything going to a spouse or charity)

Federal exclusion (the amount free of federal estate tax)

One person, $15,000,000Plus a late spouse's full unused exclusion, $30,000,000

A late spouse's unused exclusion can be added to yours only under federal law, and only if their estate filed a return in time to claim it. The amount carried over is whatever the first estate did not use. Illinois gives $4,000,000 per person and carries nothing over between spouses, whichever you choose here.

Refine for property outside Illinois, or try the proposed law

Share of the estate located in Illinois

Illinois exclusion (the amount free of Illinois estate tax)

2026 law, $4,000,000As SB 3847 would set it, $8,000,000 (not law)

Illinois estate tax: $456,071
Federal estate tax: $0
Both taxes combined: $456,0717.6% of the estate

Illinois is the only estate tax that applies at this size. The estate is over the Illinois exclusion but under the federal one.

This is a simplified model, not your actual tax return or plan. It only knows what you type in, leaves out rules that may apply to you, and cannot weigh the other facts and trade-offs a real decision depends on. Before you act, talk with a professional who knows your whole situation.

Educational only, not investment, tax, or legal advice. Results are hypothetical estimates that vary with each use and over time and are not guaranteed accurate or complete. Using this tool creates no client relationship with Considerate Capital, and the site that linked here is not affiliated with it. By using it you agree to the tool terms.