How Property Taxes, HOA Dues, and Interest Are Prorated Between Buyer and Seller at Closing

When friends split a restaurant tab, the math is straightforward: you pay for the exact items you ordered. But when a buyer and seller sit down at a real estate closing table, they are splitting a continuous stream of ongoing costs—property taxes, homeowner association dues, and utility bills—where the dividing line is not an itemized list, but the exact day the keys change hands.

The mechanism that handles this division is called proration. As Neighborhood Escrow explains, "Proration ensures that each party is only responsible for the property expenses during the time they actually own the property." This prevents either party from subsidizing the other's living expenses.[2]

Step 1: Identify the exact closing date and assign ownership for that day. In most U.S. jurisdictions, the buyer is considered the owner of the property on the day of closing. If a transaction closes on September 15, 2026, the seller is responsible for all costs up to September 14, and the buyer assumes the financial burden starting at midnight on the 15th.[1]

Step 2: Determine the billing cycle for each specific expense. This is where the math diverges based on local custom. Some costs, like homeowner association (HOA) dues, are billed in advance. If the seller already paid the $300 September HOA fee on the first of the month, the buyer must reimburse the seller for the 16 days they will own the home in September.[2]

Property taxes, however, are frequently billed in arrears. The Law Office of Andrew Szocka notes that understanding this timeline is the crucial "explanation behind the equation" at the closing table, as it dictates who owes whom.

In states that bill in arrears, the seller has been living in the home while racking up a tax bill that will not be issued until the following year. Yonas and Phillabaum LLC points out that "in Ohio, real estate taxes are billed in arrears, meaning the bill you receive in 2026 is actually for the 2025 tax year."

Step 3: Calculate the daily rate, known as the per diem. To divide an annual property tax bill of $6,000, the title company divides the total by the number of days in the year to establish a baseline cost of ownership per day.

While a standard calendar year has 365 days, yielding a daily rate of $16.43 on a $6,000 bill, some escrow companies use a 360-day statutory "banker's year" for their calculations. This shifts the daily rate slightly to $16.66, a small variance that scales up on luxury properties.[1][2]

Step 4: Count the exact number of days the seller owned the property during the current billing cycle. If the tax year began on January 1, 2026, and the closing takes place on September 15, the seller has owned the home for 257 days.[3]

Step 5: Allocate the credits and debits on the Closing Disclosure. Using the 365-day math, the seller owes 257 days of taxes at $16.43 per day, totaling $4,222.51. Because the buyer will eventually receive the full 2026 tax bill from the county, the seller gives the buyer a credit for this exact amount at closing.

Step 6: Calculate the prepaid interest for the buyer's new mortgage. Unlike rent, mortgage interest is paid in arrears, but lenders require buyers to prepay the interest for the remainder of the closing month before the regular payment schedule begins.[1]

If the buyer's new loan carries a daily interest charge of $45, and they close on September 15, they must bring $720 to the closing table to cover the 16 days of interest remaining in September. This aligns their first official mortgage payment to begin on November 1, which will pay the interest accrued throughout October.[2]

Step 7: Reconcile the final cash-to-close figures. The timing of the closing date acts as a financial lever. Closing late in the month reduces the buyer's prepaid interest burden but increases their reimbursement to the seller for advance-billed items like HOA dues.[3]

Conversely, closing early in the month forces the buyer to bring more cash to cover prepaid mortgage interest, while maximizing the tax credit they receive from the seller in arrears-billing states.

The final Closing Disclosure consolidates these per-diem calculations into a single net figure. By verifying the daily rates and the exact day counts, both parties ensure they are paying precisely for their own time in the property, down to the final midnight.[1][2]