What Is Prorated Mortgage Interest When Selling a Home?
Sellers are sometimes surprised that the amount owed to close out a mortgage is a little higher than the loan balance shown on their most recent statement, and the gap almost always comes down to interest that accrued in between.
The short answer
Most mortgages charge interest in arrears, meaning each monthly payment covers interest for the previous month rather than the month ahead. When a loan is paid off mid-month through a home sale, the payoff amount includes not just the remaining principal but also interest that has accrued from the last payment date up through the closing date — prorated for the exact number of days involved.
Why interest accrues between payments
Interest on most mortgages is calculated daily based on the outstanding principal balance, then totaled and billed once a month. Because mortgage amortization is structured this way, a loan is never fully “caught up” until the very day a payment is made — there’s always some amount of interest accruing between one payment and the next. Selling in the middle of that cycle means the loan gets paid off before the next scheduled payment would have caught it up on its own.
How the per-diem amount is calculated
Lenders typically calculate a per-diem interest figure by taking the annual interest rate, applying it to the current principal balance, and dividing by the number of days in the year, which produces a daily interest cost. That daily figure is then multiplied by the number of days between the last paid-through date and the closing date to arrive at the prorated interest owed. This calculation is included directly in a document known as a payoff quote, described further in how a mortgage gets paid off at closing.
Why the timing of closing can matter
Because interest keeps accruing daily until the loan is actually paid, closing later in the month generally means more prorated interest has built up since the last payment, compared to closing right after a payment was made. This isn’t a penalty — it’s simply the cost of borrowing for those additional days — but it can influence how sellers think about the ideal timing of a closing date relative to their existing payment schedule.
What this means for net proceeds
Prorated interest is deducted from the sale proceeds as part of the payoff amount, alongside the outstanding principal, so it reduces what a seller nets from the transaction by a relatively small amount compared to the loan balance itself. It shows up as part of the total payoff figure on the closing statement rather than as its own separate deduction, which is part of why selling a home with a mortgage still in place can look like a slightly bigger deduction than the last statement balance suggested.
What to weigh
Prorated interest is a routine, predictable part of paying off a mortgage at a home sale rather than a fee to negotiate around. Reviewing the payoff statement’s per-diem figure and closing date ahead of time gives a clearer sense of the exact amount that will be deducted, rather than relying on an older account balance that doesn’t reflect interest accrued since the last payment.