There is a stretch of $1.36 million in Illinois that costs more per dollar than any other money a family can own.
It runs from $4,000,000 to about $5,360,000. Inside that band, Illinois takes about 28.6 cents of every dollar. Above it, the cost of the next dollar falls to about 10.2 cents.
The family at $5 million pays a higher Illinois estate tax rate on its next dollar than the family at $20 million (although the second family might have Federal estate tax to consider too).
Why the rate drops
Illinois runs two calculations. One uses its own brackets. One uses the federal tables. The state applies the lower of the two.
Below the crossover, the state's own math produces the smaller number, and that math is steep. Above the crossover, near $5.36 million, the federal table takes over and the next dollar gets cheaper.
So the band just over the line is almost three times as expensive to sit in as everything above it.
There is no cliff
You may have read that one dollar over $4 million makes your whole estate taxable. That is not how it works.
An Illinois estate of $4,100,000 owes about $28,571. Real money, not six figures. An estate of $5,000,000 owes about $285,714. At the top of the band, around $5,360,000, the bill is roughly $388,000.
The tax phases in. It does not fall off a shelf. That matters, because families who believe the cliff story either panic or give up, and neither one of them plans.
Who is actually in this band
The people in the most expensive $1.36 million are rarely the people who think of themselves as wealthy.
A house in DuPage County worth $700,000. A life insurance policy that pays $1,000,000. An IRA that grew for thirty years of a good career. Two cars, a cabin, and a brokerage account built on payroll deductions.
Add those up and a family is at $4 million without anyone ever feeling rich. Nobody bought a plane.
Illinois counts the house. It counts the retirement accounts. It counts the life insurance death benefit. That last one surprises people most, because they bought the policy to take care of the family, not to add to a tax base.
A couple at $5 million
Take a hypothetical couple in Naperville with three children and six grandchildren. Their estate is $5,000,000. They are squarely inside the expensive band.
If nothing changes, the Illinois bill (probably at the second death but maybe at first) is about $285,714.
Here is the arithmetic that moves it. The annual gift exclusion in 2026 is $19,000 per giver per recipient, or $38,000 from a married couple. Nine people times $38,000 is $342,000 that can leave the estate in one year.
Illinois has no gift tax, so those dollars leave the estate when they leave the account. Three Januarys of that moves $1,026,000 and puts the couple under $4,000,000.
Every dollar they move back under the line was a dollar costing about 28.6 cents. It is the most expensive money to keep and the most productive money to move.
One caution on strategy inside this band. A gift that uses federal exemption, rather than the annual exclusion, gets added back into the Illinois calculation at death. If a family between $4,000,000 and about $5,360,000 is told to "use the federal exemption," that advice may do very little for Illinois. The channels that work here are the ones that never come back into the base.
The channels that stay out
Four of them do the work.
Annual exclusion checks. $19,000 per person, $38,000 from a couple, every year, with no gift tax return to file. The allowance is use it or lose it. Skip a year and $19,000 or $38,000 is stuck in the estate for good. For the family above, that could cost the kids $10,868 in estate tax.
Tuition paid directly to the school, and medical bills paid directly to the provider. Those are not gifts at all, in any amount. The check has to go to the institution, not to the person.
529 plans. A single giver can front-load five years of annual exclusion gifts at once, $95,000 per beneficiary, or $190,000 from a married couple. Keep in mind that a withdrawal not used for qualified education costs brings income tax on the earnings plus a 10% additional tax on the earnings.
Gifts in trust. A check to your married son can be his separate property under Illinois law, until it lands in the joint account. The same dollars placed in a trust can stay his through a divorce or a lawsuit, if the plan is built and handled right. A trust gift also needs an account, a trustee, and maybe even withdrawal notices in the file to earn the exclusion. That plumbing takes time, which is why November is a better month for this than December.
What to do with this
Find your number first. Add the house at today's value, the retirement accounts at today's balance, the life insurance death benefit, and everything else. Then see which of the four bands you land in: under $4 million, $4 million to about $5.36 million, about $5.36 million to about $15 million, or above that, where the federal estate tax joins in.
If you land in the expensive band, each dollar you move out is a dollar that was costing about 28.6 cents. The arithmetic is not complicated. It is just annual.
Yearly gifting is one piece of estate planning work, not a substitute for it. The first conversation is free. Book a Legacy Mapping Session.