At a glance
| State estate tax | Yes — exemption $4,000,00035 ILCS 405/2 / Ill. Att'y Gen. Estate Tax Fact Sheet · 2026 |
|---|---|
| Estate top rate | 16%35 ILCS 405/2 (incorporates IRC § 2011 credit table) · 2013 |
| Inheritance tax | No |
| Small-estate ceiling | $150,000755 ILCS 5/25-1 (P.A. 104-346, eff. Aug 15, 2025) · 2025 |
| TOD deed for real estate | Available755 ILCS 27 (Real Property TOD Instrument Act) · current |
| Community-property state | No |
Estate tax
Illinois imposes an estate tax with a $4,000,000 exclusion, fixed by 35 ILCS 405/2 for deaths on or after January 1, 2013 and not indexed for inflation. It has not changed for 2026 — a 2025 bill to raise it to $8,000,000 (HB2601) stalled in committee. Because it sits far below the federal exemption, many estates that owe no federal tax still owe Illinois tax.
Illinois does not use a flat rate. The tax runs through an "interrelated calculation" tied to the old federal state-death-tax credit table (IRC § 2011), which tops out at a 16% marginal rate. Effective rates just above the threshold are steep: the Attorney General's own examples show a $4,000,000 Illinois estate owes $0 while a $5,000,000 Illinois estate owes $285,714.
The $4,000,000 exclusion is a cliff — an estate above it is taxed on the full base, not just the excess. Illinois has no portability, but it permits a separate state QTIP election under 35 ILCS 405/2(b-1), independent of the federal election, so a married couple can defer Illinois tax on the first death and use both $4,000,000 exclusions. Unusually, the tax is administered by the Illinois Attorney General, not a revenue department.
Inheritance tax
Illinois has no inheritance tax — beneficiaries are not taxed on what they receive by the state. Illinois imposes no inheritance tax; the Attorney General administers only the estate tax under 35 ILCS 405.
Probate basics
A small-estate affidavit under 755 ILCS 5/25-1 may be used where the personal estate does not exceed $150,000 (excluding registered vehicles), avoiding probate. Estates that must be administered can use independent administration with minimal court supervision.
Illinois is a common-law (separate-property) state for ownership between spouses. A transfer-on-death deed for real estate is Available 755 ILCS 27 (Real Property TOD Instrument Act) · current. The probate deadlines for this state — filing the will, the creditor-claim window, the inventory — are cited in the Executor & Heir’s Guide.
State-specific quirks
A $4M exclusion frozen since 2013
Illinois recognizes only $4,000,000, far below the federal exemption, so many estates that owe no federal tax still owe Illinois estate tax. The figure is not indexed and has not moved since 2013.
The exclusion is a cliff, not a deduction
Once the estate exceeds $4,000,000, the tax is computed on the whole taxable base, not just the amount over $4,000,000. Per the Attorney General's examples, a $5,000,000 Illinois estate owes $285,714 — a large bill for being $1,000,000 over.
No portability, but a separate Illinois QTIP
Illinois does not let a surviving spouse inherit an unused exclusion. Married couples instead rely on the separate state QTIP election under 35 ILCS 405/2(b-1), which can be made independent of the federal election, to preserve both $4,000,000 exclusions.
Where to read next
- the federal lifetime exemption — how the far larger federal exclusion works — and why a state tax can still apply below it
- funding a revocable trust — the most common way to keep property out of probate entirely
- the ILIT cluster — keeping a life-insurance death benefit out of a taxable estate
- the Executor & Heir's Guide — the probate deadlines for this state, cited to the statute
- ← Back to the 51-jurisdiction comparison
Sources & methodology
Methodology & sources
Every tax figure on this page links to the primary source it was verified against — a Illinois statute or department-of-revenue page — with that source’s own effective date. Aggregator round-ups are never used as a source. State death and probate law changes every legislative session; this page carries the date it was last re-verified, and any figure that could not be confirmed from a primary source is flagged for you to check with the state rather than guessed. See our editorial standards.
This page is educational and is not legal or tax advice. Whether a death tax applies turns on residency, where property sits, and how title is held — details a general page cannot resolve. Confirm your own situation with a professional licensed in Illinois.
Last verified July 20, 2026.