The four-million-dollar line.

Sooner or later you make the list. At the kitchen table, on a yellow pad: the house you bought for a third of what it would sell for now, the retirement accounts that compounded quietly while the kids grew up, maybe a business or a piece of farmland, and the life insurance you signed at 40 because the mortgage scared you. The number at the bottom surprises you. Sometimes the list gets made after a 70th birthday, sometimes after a friend's funeral; either way, you were not thinking about taxes when you added it up. You were thinking about the person across the table. By Illinois standards, though, the page in front of you may be something you never thought you had: a taxable estate.

Most of the country has stopped thinking about estate tax, for good reason. The federal exclusion is $15,000,000 per person in 2026, which puts it out of reach of nearly everyone.¹ Illinois did not follow. It draws its own line at $4,000,000, with its own rules, its own return, and its own way of counting, administered not by the IRS but by the Illinois Attorney General.² If your yellow pad holds an ordinary amount of Midwestern good fortune, the federal tax is a rumor. The Illinois tax is a real bill.

Where the line actually sits

One word of orientation first: this is an estate tax, levied on the estate itself before anything passes, not an inheritance tax collected from the people who receive it. Your heirs do not get separate bills; the estate settles one.

The first job is honest counting, because your estate is bigger than it feels. Everything you own at death counts toward the line: the house at what it would sell for this spring, not what you paid in 1992; the retirement and brokerage accounts; the business at what a buyer would pay, not what the books say; the farmland your father bought by the acre, valued by today's acre; and, the one that surprises nearly everyone, the life insurance. The policy you bought so the mortgage would die with you pays your family income-tax free, but its death benefit lands inside your taxable estate, and it is very good at turning a list that reads $3.6 million into one that reads $4.4.³

Two more counting rules matter. Large gifts you made during life are added back when Illinois checks whether your estate must file, so giving assets away on paper does not make the line forget you, even though what gets taxed is what you still own.² And the line belongs to each person, not each couple: $4 million for you, $4 million for your spouse, with consequences we will get to.

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For most Illinois families, the federal estate tax is a rumor and the Illinois estate tax is a real bill. The difference is the line at four million dollars.

What crossing it costs

Start with who actually pays it, because it is not you. The bill arrives about 9 months after the funeral, made out from your estate, signed by whoever you loved enough to name as executor, in the same season they are still forwarding your mail. What they owe turns on a line you may never have known you crossed, and it works differently than people assume: the $4 million is not a deduction, where only the excess is taxed. Once an estate crosses it, Illinois computes tax on the whole taxable estate, at graduated rates that run to 16%, through an interrelated calculation strange enough that the Attorney General publishes a calculator for it.²

The state's own published examples make the shape of it plain: an estate of exactly $4,000,000 owes $0. An estate of $5,000,000 owes $285,714.³ So what does being a single dollar over actually cost? Almost nothing, it turns out: run the Attorney General's own calculation on $4,000,001 and the tax comes to about 29 cents, which the state's calculator displays as $0.¹¹ The internet's "$1 over costs you hundreds of thousands" story is a myth. The truth is a ramp, and it is steep: from the first dollar past the line, each additional dollar of estate costs about 28.6 cents of tax, all the way to roughly $5.5 million, before the graduated schedule eases the slope. And on the estates this state grows best, the farm the kids learned to drive on, the shop, the building with the family name on the lease, that arithmetic is not abstract. The tax is due in cash. When the estate is land and equipment rather than brokerage balances, the money has to come from somewhere, and sometimes it comes from selling the one thing everyone meant to keep.

Rather than make you read a tax table, we built the state's computation into a calculator. Your number, and the federal one beside it, is one input away.

Two things the calculator will show you are worth saying out loud. First, here is the part that surprises people: until your estate is quite large, Illinois is the only one taxing it, not the federal government. The Illinois bill is subtracted before the federal math even starts, and that keeps the federal tax at zero until one person's estate reaches roughly 17 million dollars.¹¹ A widow or widower who carried over a late spouse's unused federal exemption can shelter up to $30,000,000 federally, which pushes the federal side of this page out past $34 million; Illinois lets you carry over nothing from a late spouse, so the survivor still gets only one $4,000,000 exemption.¹ Second, even as the marginal rates ease, the total keeps climbing: by $25 million the two taxes together claim roughly 23% of the estate. And the $285,714 at $5 million is money a family feels: a grandchild's college, ten years of property taxes on the home place, the cushion that was supposed to make the survivor's decade easier. Almost none of it has to be owed by accident, and most of what follows is about the lawful, well-worn ways families keep from paying it that way.

The married-couple trap

The costliest mistake in Illinois estate planning is also the most natural-sounding sentence in any will, very possibly in yours: everything to my spouse.

Property passing outright to a surviving spouse is generally fully deductible, so the first death usually produces no tax at any size. The trap is what it does to the second death. The federal system lets a surviving spouse inherit the unused exclusion, a feature called portability. Illinois pointedly does not; the Attorney General's instructions state that the carry-over of unused exemption to the surviving spouse is inapplicable to the Illinois tax.⁴ So when everything passes outright to the survivor, the first spouse's $4 million exclusion simply evaporates. A couple with $7 million has, together, $8 million of Illinois exclusions; the simple plan leaves the survivor holding a $7 million estate and only one $4 million shield. And notice who pays for the simplicity: not the two of you, the one of you. The survivor files the first single tax return, meets the widow's penalty, and then, years later, faces Illinois with half the protection the marriage had earned. "Everything to my spouse" was written as an act of love. The trust version is the same love with the paperwork finished.

The old remedy still works, and in practice it is built while you are both alive, out of pieces that cost you nothing while you are both alive: each of you gets a revocable living trust, fully changeable for as long as you live, with the dividing already written inside it. At the first death, the deceased spouse's trust splits itself. A family trust, sometimes called a credit shelter or bypass trust, takes the first $4 million, using their Illinois exclusion and sitting outside your taxable estate while still able to support you. A second trust, the kind lawyers call a marital or QTIP trust, holds the rest for you to live on, and nothing passing to a spouse is taxed at the first death. The unspoken part is that drafting this means the two of you will sit in a lawyer's office and talk, once, about which of you might go first. That hour is most of the price. The documents hold the answer from then on, so the one left never has to engineer it alone, in the worst month. Drawn the way an estate attorney would sketch it on the same yellow pad:

If your list sits between the Illinois and federal lines, the QTIP side does double duty: Illinois lets you make a special election on that second trust that shelters the in-between amount at the first death, so the survivor owes Illinois nothing then. The state's instructions show an estate of $13,610,000 paying $0 at the first death with a $9,610,000 Illinois QTIP election.⁵ Two cautions come with that: the election only exists if the first estate actually files an Illinois return and makes it, even when no tax is due, which is precisely the filing that is easiest to skip in the fog of that first year; and the drafting belongs to an estate attorney, not a template.

If you would rather not lock the split in ahead of time, disclaimer planning leaves the choice with whichever of you is left: within a strict 9-month window, the survivor can formally decline part of the inheritance, which is what the law calls a disclaimer, and steer that amount into the shelter trust based on the numbers as they actually stand.⁶ It is flexibility with a deadline, and the documents have to be written for it in advance.

What you can do while you are alive

Lifetime giving is the unglamorous workhorse. In 2026 you can give $19,000 per recipient per year, $38,000 from a couple, without touching either the federal or Illinois math.¹ Three children and their spouses can quietly receive $228,000 a year from a couple this way; do that for a decade and the line recedes considerably, while the growth on what you gave compounds in your children's hands instead of your estate. One trade is worth knowing: if you hand over appreciated investments rather than cash, they keep your original cost, so your children can owe capital-gains tax later that inheriting the same asset at your death would have erased. And there is the part no table can show: money given while you are alive turns into things you are still here to see, the kitchen, the degree, the down payment that became a front door with grandchildren behind it. Illinois has no gift tax of its own, and while larger gifts count toward whether your estate must file, they leave the taxed base, taking all their future appreciation with them.²

Life insurance deserves its own sentence, because it sits on both sides of this problem. The policy you bought to protect them inflates the estate when you own it yourself. Owned outside you, typically by an irrevocable life insurance trust set up from the start, the same policy does the opposite of harm: it pays outside the estate entirely, and it is often the very thing that hands your kids the cash to pay an estate tax without selling the land or the business to do it. The trap is retrofitting: transfer an existing policy into a trust and the proceeds are pulled back into your estate if you die within 3 years of the transfer.⁷ Buy it right the first time if you can.

Charity is the cleanest line item of all: everything passing to charity deducts fully, from both the federal and Illinois calculations. And for larger or more complicated estates there is a deeper toolbox, trusts with acronyms, valuation discounts, generation-skipping structures, that belongs entirely to a good estate attorney's craft and is beyond a page like this one.

The Florida question

Eventually someone at the kitchen table says it: we could just move. Sometimes that is right, and people do it for sunshine as much as taxes. But know what moving does and does not do. Illinois taxes the worldwide estate of people domiciled here, and domicile is a real legal standard about where your life actually is, not where your mail forwards. And it does not release the land: Illinois real estate and tangible property stay in the Illinois calculation no matter where you die. The state's own example shows a $5 million estate split evenly between Illinois and Florida still owing $142,857 to Illinois, even though Florida has no estate tax at all.⁸ You can move yourself. You cannot move the farm. And before the tax makes the decision for you, weigh what the move actually trades: the pew you have sat in for 30 years, the doctor who knows your history without the chart, Sunday dinner 20 minutes away. Florida is a good answer to winter. It is a thin answer to a tax you can usually plan around from home.

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You can move yourself. You cannot move the farm.

The same arithmetic runs in your favor, though, and this is the part people miss. Illinois computes the tax on the whole estate and then subtracts the share that legally counts as located in another state, so property genuinely sited elsewhere, like out-of-state real estate, does not just escape Illinois; it shrinks the Illinois bill in proportion.⁸ In the state's own example, an estate with half its property outside Illinois owed exactly half the tax, $142,857 instead of $285,714. The Wisconsin lake house and the Arizona condo are quietly working against the Illinois number every year you own them. Which assets count as sited elsewhere is a real legal question, classically real estate and tangible property located in the other state, and the answer belongs on the tax return, worked out with your attorney, not in a guess.

When none of this is your problem

Honesty requires the other half. If your honest count, life insurance included, sits comfortably below $4 million, the Illinois estate tax is not your problem, and trust structures bought out of generalized anxiety are cost without benefit. If that is you, take the quiet win and close this page in peace; a current will and clean beneficiary forms are your whole assignment, and a family that does not need a trust is not a family that is behind. If your estate passes to your spouse and then to charity, the deductions already do the work. And the law itself may move: a bill pending in Springfield as of mid-2026 would raise the exclusion to $8,000,000 in 2027 and add portability, and separate proposals for family farms have been introduced and stalled before; none of it is law today, and a plan built on a pending bill is not a plan.⁹ What this means in practice is simple: count honestly first, plan to the law that exists, and have the plan reviewed when the law changes, because both directions of error, planning you did not need and exposure you did not see, cost real money.

The mechanics, for whoever settles the estate: when an estate over the line exists, an Illinois return is due, with the tax, 9 months after death, filed with the Attorney General and paid to the State Treasurer; extensions exist, and estates built around a farm or business may qualify to pay in installments.¹⁰

Where we fit in. We integrate tax considerations into your investment strategy and collaborate with estate attorneys and CPAs to ensure your plan is coordinated. We are not a law firm or accounting firm, so we do not provide legal or tax advice. Everything in this material is for educational purposes, based on primary sources. Before taking any action, please consult the appropriate professionals to apply these ideas to your situation.

The pattern, though, is worth keeping: in Illinois, the estate tax is mostly a tax on not counting. And counting, it turns out, is something the two of you can still do for each other, on a yellow pad, at the same table where this article began. The families who pay it by accident are rarely the richest ones; they are the ones who never added the life insurance to the yellow pad, or whose wills said the simplest possible sentence. If your list is anywhere near the line, that is worth one unhurried conversation, and there is time set aside on our schedule page. We wrote separately about the deadlines and elections that follow a death, including the disclaimer window and federal portability, in the money mistakes that follow a loss.