How Property Tax Proration Works at Closing

A property tax bill covers a period - a year, a half-year, a quarter - and a closing almost never lands on the first day of one. Proration divides that bill between the parties according to how much of the period each of them owned the property. The seller carries the days up to closing and the buyer carries the days after.

The mechanics are simple arithmetic. What makes prorations error-prone is everything around the arithmetic: which convention the closing date follows, whether the bill has already been paid, and by whom.

The calculation

Every proration reduces to a per diem multiplied by a day count:

per diem = amount due / days in the tax period seller's share = per diem × days the seller is responsible for buyer's share = amount due - seller's share

The buyer's share is always the remainder of the period rather than a second independent calculation. That matters: it guarantees the two shares add back to the bill exactly, with no rounding drift between them.

Does the closing date count as a seller day?

There is no universal answer. Some jurisdictions count the day of closing as a seller day; others give it to the buyer. The purchase contract may settle it, and where it does, the contract wins. On a large annual bill the difference is one per diem - small, but it is the kind of discrepancy that surfaces at the table when the other side's figure is a few dollars off yours.

Whatever convention you follow, apply it consistently across every proration on the file.

Payment status changes who pays, not the shares

The buyer's and seller's shares are a function of the calendar. They do not change based on who has already paid the bill. What the payment status changes is the direction the money moves at closing:

Status	What happens at closing
Unpaid	Nobody has paid the taxing authority yet. The shares are still calculated, but nothing is adjusted between the parties on this basis alone - once you know who will carry the bill, record it as paid by that party so the credit is raised.
Paid by seller	The seller has already paid the full period. The buyer reimburses the buyer's share.
Paid by buyer	The buyer will carry the full bill. The seller credits the seller's share.
Paid through closing	The period is settled up to the closing date, so there is nothing left to adjust between the parties.

The commonest proration error is not the arithmetic It is calculating the shares correctly and then crediting the wrong party, because the bill's payment status was assumed rather than confirmed. Check the status against the actual tax record, not the contract.

More than one tax gets prorated

Property tax is the obvious one, but most closings carry several recurring charges that split the same way, each with its own period, amount and taxing authority:

City and county property taxes, which frequently run on different periods from each other
School taxes, often on a school year rather than a calendar or fiscal year
Special assessments - improvement districts, and similar recurring levies
Sewer and other municipal service charges billed on a period
Village taxes, where the property sits inside one

Each is prorated independently. A closing with a city bill on a calendar year, a county bill on a fiscal year and a school bill on a school year has three different day counts running at once, and combining them into a single "taxes" line is how the total ends up wrong.

Period bases

The period determines the denominator of the per diem. Annual, semi-annual, quarterly, monthly, school-year and village bases all appear in practice, and picking the wrong one silently scales every figure that follows.

Where the numbers go next

A proration is not finished when the shares are known. The result has to reach the settlement statement as a credit or debit to the right party, and reach the disbursement ledger so the money actually moves. Where the lender escrows taxes, the monthly figure also feeds the escrow section of the Closing Disclosure - which means the same underlying bill can appear in more than one place on the form, calculated on a different basis each time.

That is the real work in prorations: not any single division, but keeping every derived figure consistent with the source bill as the closing date moves.

Try the numbers The free tax proration calculator runs this calculation - per diem, both shares, and the net owed at closing - with no signup and nothing saved.

Common questions

Who pays the property taxes at a real estate closing?

Both parties pay, in proportion to the part of the tax period each of them owned the property. The seller is responsible for the days up to closing and the buyer for the days after. Whichever party actually pays the taxing authority is reimbursed for the other party's share at closing.

How is the per diem for a tax proration calculated?

Divide the amount due for the period by the number of days in that period. The seller's share is the per diem multiplied by the number of days the seller is responsible for, and the buyer's share is the remainder of the bill.

Does the day of closing count as a seller day?

It depends on local custom and on what the purchase contract says. Some jurisdictions count the closing date as a seller day and others assign it to the buyer. Where the contract addresses it, follow the contract, and apply the same convention consistently across every proration on the file.

What happens if the seller already paid the tax bill?

The shares are unchanged - they depend only on the calendar. Because the seller has paid the whole period, the buyer reimburses the buyer's share at closing rather than the seller crediting the buyer.

Which charges besides property tax get prorated?

Any recurring charge billed on a period: city and county taxes, school taxes, special assessments, sewer and other municipal service charges, and village taxes. Each has its own period and day count and is prorated separately.