You close a rental on the nineteenth of September. The loan officer tells you your first payment is due November first. You do the math twice because it does not sound right. You borrowed money in September and your first payment is not until November, which is six weeks later, and nobody seems to think this is unusual. Then you look at your settlement statement and find a line called prepaid interest, or interim interest, or per diem interest, charging you 428 dollars you did not budget for.
You did not skip a month. You paid for it at the closing table, in advance, in cash. Almost every investor gets this backwards, and the ones who get it right save real money by choosing their closing date deliberately.
Want your cash to close broken down line by line before you pick a closing date? Send the address, the loan amount, and the target date. We will show you exactly what the prepaids and escrows add and what moving the date would do to them. No cost, no obligation.
Send it here or call 412-990-2941. FMC Capital, NMLS #1840537.
We finance investment properties for investors across Pennsylvania and additional states, and cash to close surprises are the single most common complaint we hear in the last week of a transaction. This guide explains prepaid interest on a rental loan, why the first payment date lands where it does, and the one scheduling decision that can move a few hundred dollars back into your pocket.
Mortgages are paid in arrears, and that explains everything
Rent is paid in advance. You pay on the first for the month you are about to live in. Almost every investor’s intuition about payment timing comes from rent, and mortgages work the opposite way.
A mortgage payment is paid in arrears, meaning the payment you make on November first covers the interest that accrued during October. You are paying for a month you already had the money. That single fact produces the entire structure of what happens at closing.
Follow the timeline. You close September nineteenth, so you have the lender’s money from the nineteenth onward. September nineteenth through September thirtieth is twelve days of interest that belongs to the lender and is not covered by any scheduled payment, because there is no payment cycle that ends in September. October first through October thirty first will be covered by the November first payment. So the twelve orphaned days in September have to be collected somewhere, and the only place available is closing.
That is prepaid interest. It is not a fee, it is not a markup, and it is not the lender being clever. It is the interest for the stub period between your funding date and the start of your first full payment cycle.
The math, exactly
The calculation is one of the few in mortgage lending you can verify yourself in thirty seconds.
Take the loan amount, multiply by the annual interest rate, divide by three hundred sixty five to get the daily interest, then multiply by the number of days remaining in the closing month including the closing day.
On a 245,000 dollar loan at 7.25 percent, the annual interest is 17,762.50 dollars. Divided by three hundred sixty five, the per diem is 48.66 dollars. Closing September nineteenth leaves twelve days in September, so the prepaid interest is 583.92 dollars.
Close on September third instead, and you have twenty eight days remaining, which is 1,362.48 dollars. Close on September twenty eighth and you have three days, which is 145.98 dollars.
Same loan, same rate, same property. A 1,216 dollar swing in cash to close driven entirely by which day of the month you sign. That is the lever, and it is available on nearly every transaction where the seller is flexible.
Why skipping a month is a myth worth killing
Loan officers say it constantly and it is not malicious, but it is wrong in a way that costs borrowers money because it makes them stop paying attention.
You do not skip October. You prepay part of September at closing and then the November first payment covers October in full. There is no free month anywhere in the sequence. What actually happens is that your cash outlay is front loaded: you pay some interest early, in cash, at a moment when you are already writing the largest check of the transaction, and the size of that early payment is inversely related to how late in the month you close.
The reason this matters is that investors budgeting cash to close often model the down payment, the closing costs, and the escrow setup and treat prepaid interest as a rounding error. On a larger loan closing early in the month it is not a rounding error. On a 600,000 dollar loan at 7.5 percent closing on the second, it is over 3,600 dollars.
The other prepaid: escrow seeding, which is not the same thing
Prepaid interest gets confused with escrow funding constantly, and they are unrelated.
Prepaid interest pays the lender for days you have already had the money. It is gone. It buys you nothing and returns nothing.
Escrow seeding is you funding your own account. The lender collects a few months of taxes and insurance up front so the impound account has a cushion when the first tax bill arrives. That money is still yours. It sits in the escrow account, it pays your bills, and if the account is overfunded you get it back. The mechanics of how the account is funded and how much it adds at closing are in our guide to escrow and impounds on a rental loan, and whether you can avoid the account entirely is covered in our guide to DSCR loan escrow waivers.
The distinction is worth internalizing because it changes what you should optimize. Escrow seeding is a transfer from your left pocket to your right pocket, so moving it around does not really save you anything. Prepaid interest is a genuine expense, so timing it well is genuine savings. Investors frequently negotiate hard on the escrow number and ignore the interest number, which is backwards.
The worked file
Put the whole cash to close together on a real deal, because prepaid interest only makes sense in context.
A duplex at 285,000 dollars. Twenty five percent down is 71,250 dollars, so the loan is 213,750 dollars at 7.25 percent. Rents are 1,250 and 1,175 dollars, so 2,425 dollars a month. The payment of principal, interest, taxes, and insurance comes to about 1,940 dollars. The coverage ratio is 2,425 divided by 1,940, which is 1.25.
Now the cash. Down payment 71,250 dollars. Lender fees, title, and recording, call it 6,800 dollars. Escrow seeding of three months of taxes and two months of insurance, roughly 1,850 dollars. Per diem on this loan is 213,750 times 0.0725 divided by 365, which is 42.46 dollars a day.
Close on the fourth of the month: twenty seven days, 1,146.42 dollars of prepaid interest. Total cash to close roughly 81,046 dollars.
Close on the twenty sixth: five days, 212.30 dollars. Total cash roughly 80,112 dollars.
The difference is 934 dollars, which on this deal is about forty percent of a month’s gross rent, obtained by changing a date on a contract. Nobody underwrote anything differently. You can layer this into your own numbers on our DSCR deal calculator to see the ratio and then add the prepaids on top.
The correction: late is not always better
Here is the part that keeps this from being a simple rule, and it is the reason we do not tell every client to close on the twenty eighth.
Closing late in the month minimizes prepaid interest but it also delays your first rent collection and it compresses your funding window. Three specific costs.
First, rent proration. On an occupied rental you receive the seller’s collected rent for the days you own the property. Close on the fourth and you get twenty seven days of rent credited to you at closing. Close on the twenty sixth and you get five. On the duplex above, that is roughly 1,780 dollars of rent credit you gave up to save 934 dollars of interest. The rent credit is larger than the interest savings, and it moves in the opposite direction. How that credit appears on your statement is covered in our guide to prorations at closing.
Second, month end congestion. Title companies, appraisers, and funders are busiest in the last three business days of the month. A file scheduled for the twenty ninth that slips is not slipping two days, it is often slipping into the next month entirely, which resets your whole prepaid calculation and can blow a rate lock.
Third, the interest is not saved, it is deferred. You will pay interest on that money eventually. Closing late does not reduce the total interest on the loan by a dollar. It reduces the amount you pay at the table, which is a liquidity benefit, not a cost benefit.
So the honest rule is narrower than the popular advice. If the property is vacant, closing later in the month is a clean liquidity win and you should ask for it. If the property is occupied and producing rent, closing earlier is usually better in total dollars, because the rent proration credit outruns the prepaid interest. Investors who apply the close late rule universally are optimizing the smaller number.
What to check on your own statement
Three things, and they take two minutes.
Confirm the per diem matches your rate and loan amount using the formula above. Errors here are rare but they happen, and they are almost always in the lender’s favor because the calculation is automated off whatever rate is in the system, which may not be the rate you locked.
Confirm the day count. Some lenders charge from the funding date and some from the disbursement date, and on a Friday closing those can differ by three days over a weekend. Three days at 48 dollars is not life changing, but it is worth knowing which convention your lender uses.
Confirm the first payment date in writing. If your closing slips from the twenty ninth to the second of the next month, your first payment date moves out a full month and your prepaid interest jumps by nearly a full month of interest. That is the single largest cash to close swing a delay can cause, and it surprises people every time.
Two related items worth reading if you are assembling cash for a purchase: where your down payment can come from is covered in our guide to gift funds and acceptable sources of cash to close, and how your earnest money flows back into the number is in our guide to how your earnest money deposit credits at closing. And once you are in the loan, if you ever pay a large chunk down and expect the payment to drop, read our guide to the DSCR loan recast, because a paydown by itself does not change your payment.
The bottom line
Prepaid interest is the interest for the days between funding and the start of your first full payment cycle, collected in cash at closing because mortgages are paid in arrears. You never skip a month. The amount is the loan times the rate divided by three hundred sixty five, times the days left in the closing month, and it can swing more than a thousand dollars on an ordinary rental purchase based on nothing but the date. Closing late in the month is the right call on a vacant property. On an occupied rental it usually is not, because the rent proration credit you forfeit is larger than the interest you save. Model both, ask for the date you want early, and check the per diem against your own arithmetic before you sign.
Want a line by line cash to close before you commit to a closing date? Send the address, loan amount, and target date through our contact page or call 412-990-2941. You can see how our rental financing works on the DSCR rental loan page and model the payment and ratio on our DSCR deal calculator.
FMC Capital is a licensed mortgage brokerage, NMLS #1840537. This article is for educational purposes only and is not a commitment to lend, an offer of credit, or financial advice. Interest calculation conventions, per diem day counts, escrow funding requirements, rates, and closing costs vary by lender, property, borrower, and market at the time of application, and are subject to change.