Closing Tool  ·  Illinois

Tax Proration Calculator

See what to expect on your closing statement. Illinois residential real estate · Cook, DuPage, Will, Kendall & Kane counties.

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County Tax Portals
Find property tax data, bills, and payment history for each county here.
Closing Details
105%
Adjust to account for anticipated tax increases. 105% is typical for suburban collar counties. 110% is common for Cook County and Chicago.
Prior Year Installment Status
Typically due June 1 (Cook County: March)
Typically due September 1 (Cook County: August)
What You'll Owe Your Buyer
Annual tax (prorated)
Days you owned the home
Daily tax rate
What you'll owe your buyer
Enter a tax bill amount and closing date to see the proration.
ⓘ This is an estimate to help you plan. Your title company or closing attorney will confirm the exact figures before closing.
What Sellers Should Know

Why the Credit Is More Than the Bill Shows

AreaTypical rate
DuPage, Will, Kane, Kendall counties105%
Cook County suburbs105–110%
City of Chicago110%

Illinois taxes are billed a year behind — the bill you have now covers last year. The extra percentage above 100% helps cover the increase your buyer will likely see on the next bill.

When Taxes Are Normally Due

Collar counties (DuPage, Will, Kane, Kendall) bill twice a year: 1st installment due June 1, 2nd due September 1.

Cook County works differently — the 1st installment (55% of last year's bill) is usually due in March, and the 2nd is billed in summer, usually due in August (sometimes later).

Confirm exact due dates for your property on the county portal before closing.

Which Tax Bill to Use

Use your most recent full-year tax bill, not a single installment. If you only have installment amounts, add both together for the annual total.

If your home was recently built or reassessed, your current bill may understate what you'll owe going forward — ask your agent whether to use the assessor's estimated value instead.

If an Installment Is Unpaid

If your last tax installment is due but you haven't paid it, you'll need to credit your buyer the full amount at closing — not just a prorated share. Your title company will flag this automatically.

If an installment isn't due yet, it's already covered by the standard credit above.

Your Exemptions Don't Transfer

If you have a homeowner, senior, or senior freeze exemption, it stays with you — it does not carry over to your buyer.

Let your agent know about any exemptions on the property so your buyer isn't surprised by a higher bill after the sale.

This Is Only an Estimate

This calculator gives you a planning estimate, not the final number. Your title company or closing attorney calculates the official proration figures used at closing.

Always confirm the exact amount with them, and verify current tax bills and due dates on the county portal, before you close.

ⓘ This calculator is a planning tool to help you understand tax prorations at closing — it is not a substitute for advice from your title company, real estate attorney, or tax professional. They will confirm the exact figures before you close. Tax bills, due dates, and rates are subject to change. Always verify current figures with the appropriate county portal. Illinois only (Cook, DuPage, Will, Kendall, Kane counties) — a Southwest Michigan version uses different tax rules and is planned separately.