Prorated property tax calculator

Buying or selling mid-year? Split the tax period and estimate the closing credit.

Property tax bill for the tax period ($)

Enter the full bill or agreed estimate for the tax period.

Closing date

Starts with January 1–December 31, 2026, with the buyer paying the bill and closing-day tax. Change these assumptions below to match your contract.

Advanced: tax period and closing terms

Tax period starts

Tax period ends

Starts with this calendar year. Change the dates to match your bill. The first and last day are included.

Who pays the tax for closing day? Who pays the entire bill for this period? Contract percentage of the bill (%)

100% uses the bill unchanged. Enter another percentage only if your contract calls for it.

Estimated closing credit $—

Fill in the form to see your split.

Estimate only. Not tax, legal or financial advice. Confirm your contract and figures with your closing agent and county.

Find your county’s official bill and dates

How the property tax proration works

For example, a $3,650 bill for a 365-day period costs $10 per day. If the seller pays for 100 days, the seller’s share is $1,000 and the buyer’s share is $2,650.

Divide the bill by the number of days in the tax period, then multiply by the seller’s days. The buyer pays the remaining share. If your contract uses a different bill percentage, apply that percentage first under Advanced.

See the formula and calculation limits

Adjusted tax = period tax × contract percentage ÷ 100. Seller’s share = adjusted tax × seller days ÷ total days. Buyer’s share is the remainder. This worksheet counts actual calendar days, including February 29 in a leap year.

Use the dates the bill covers, even if payment is due in a later year. The calculation assumes one party pays the full bill. Ask your closing agent to calculate partial payments, multiple bills, contracts that count each month as 30 days, or agreements to adjust the split when the final bill arrives.

Check the contract before using a credit

Illinois guidance describes a seller credit for the period before closing, subject to the real estate contract. Confirm the allocation in your agreement.

This is an Illinois example; your contract determines the closing-day share and bill percentage.

Sources

Checked Oct 25, 2026.

Read the source quotations (1)

https://tax.illinois.gov/questionsandanswers/answer.328.html

will provide a credit to the buyer for the time period in which the seller owned the property prior to closing

Checked Oct 25, 2026.