Per Diem Interest Calculator

A per diem interest calculator helps you estimate the daily mortgage interest you’ll pay from your closing date through the end of the month. This often-overlooked cost is collected at closing and can add up quickly, depending on when you close. With just a few simple inputs, the calculator gives you a clear, accurate estimate so you can budget smarter and even choose a closing date that saves you money.

What is Per Diem Interest on Your Mortgage?

Per diem interest represents the daily interest charge on your mortgage loan, calculated from your closing date until your first regular payment begins. Understanding this cost helps you budget accurately for closing and avoid surprises when finalizing your home purchase. Lenders collect this prepaid interest to cover the gap between when you close and when your regular monthly payment schedule starts.

How Lenders Calculate Per Diem Interest

The calculation for per diem interest follows a straightforward formula. Lenders divide your annual interest rate by 365 days to determine the daily rate, then multiply that figure by your loan amount. For example, a $200,000 loan at 6.5% annual interest generates approximately $35.62 in daily interest charges.

The number of days you pay depends on your closing date. If you close on the 15th of the month, you'll pay per diem interest for the remaining days of that month. Closing earlier in the month means paying more days of prepaid interest, while closing near the end reduces this upfront cost.

Why Per Diem Interest Exists

Mortgage payments work on an arrears system, meaning each payment covers the previous month's interest plus principal reduction. When you make your July payment, you're paying interest for June and a portion of principal. This creates a timing gap at the start of your loan that per diem interest fills.

Without collecting this prepaid interest, lenders would lose the interest income for the partial month between closing and your first payment. The per diem charge bridges this gap and ensures the lender receives appropriate compensation for the full loan period.

Impact on Your Closing Costs

Per diem interest appears on your Closing Disclosure under "Prepaids" and directly affects your cash needed to close. The amount varies based on three factors:

• Loan Amount: Larger loans generate higher daily interest charges
• Interest Rate: Higher rates increase the per diem cost
• Days Until First Payment: More days mean higher total prepaid interest
• Closing Date: Strategic timing can reduce this expense

  Many borrowers prefer closing near the end of the month to minimize per diem interest charges. However, this strategy requires careful coordination with sellers, title companies, and other parties to the transaction.

  Strategic Closing Date Selection

  Choosing your closing date affects both your per diem interest and your first payment due date. Closing on the last day of the month minimizes prepaid interest but means your first regular payment comes due in roughly 30 days. This tight timeline may strain some budgets.

  Closing earlier in the month increases per diem costs but provides nearly two months before your first regular payment. This extended period helps borrowers who need extra time to recover from closing expenses and settle into their new property.

  Per Diem Interest Across Loan Types

  All mortgage types, including conventional, FHA, VA, and USDA loans, require per diem interest at closing. The calculation method remains consistent regardless of loan program. Government-backed loans don't receive exemptions from this charge, as it represents actual interest accrued on borrowed funds.

  Refinance transactions also include per diem interest charges. When refinancing, you'll pay per diem interest on your new loan while potentially receiving a credit for interest already paid on your old loan, depending on timing.

  Recording Per Diem Interest for Tax Purposes

  Per diem interest qualifies as mortgage interest for tax deduction purposes. The amount appears on your Closing Disclosure and counts toward your total mortgage interest paid in the year of closing. Keep this document with your tax records, as you'll report it along with the mortgage interest shown on your annual Form 1098 from your lender.