Why an investment-property loan costs more
The payment formula is identical to any other mortgage. What differs is every input to it, and the differences all push the same direction.
- The rate is higher. Agency loan-level price adjustments for non-owner-occupied property are among the largest in the matrix, and they scale with loan-to-value. Lenders typically convert those points into rate, so a rental loan is quoted meaningfully above the owner-occupied rate the same borrower would get on the same day.
- The down payment is larger. Conventional programmes generally start at 15% for a one-unit investment property and require more on two-to-four units. In practice 25% down prices better than 20%, because the adjustment falls as LTV falls.
- There is no mortgage insurance. PMI is not available on investment properties, which is why the minimum down payment cannot be bridged the way it can on a primary residence. Below the programme minimum, the loan simply does not exist.
- Reserves are required. Agency guidelines require months of PITI in liquid assets for the subject property and often for each additional financed property you own.
- Insurance costs more. A landlord policy is a different product from a homeowners policy, and it usually costs more for less contents cover.
Everything else — the amortisation, the way early payments skew to interest, the effect of a shorter term — behaves exactly as on a primary residence.
The payment, and the two things that are not part of it
The monthly principal and interest is the standard amortised loan payment: M = P·r / (1 − (1 + r)^−n), where r is the annual note rate divided by twelve and n is the term in months. Divide the annual property tax and insurance by twelve, add HOA dues, and you have the full monthly obligation.
Two things people fold in that do not belong here. Vacancy, management and repairs are not part of the mortgage payment — they are operating expenses of the rental, and they belong in the rental cash flow calculator. Keeping them separate matters because the lender's payment and the property's operating statement are different documents that get compared to different things.
And escrow items are not part of the loan balance. The amortisation table on this page deliberately excludes tax, insurance and HOA, because none of them ever touches the principal. If you subtract a full escrowed payment when computing cash flow after already deducting taxes and insurance as operating expenses, you have counted them twice — the single most common double-count in rental analysis.
The rate premium is worth quantifying rather than accepting vaguely. On a $262,500 loan over thirty years, moving from 6.5% to 7.125% raises the payment from $1,659.18 to $1,768.51 — $109.33 a month, or $39,359 over the full term. That is the price of the investor designation on this one loan, and it is why occupancy misrepresentation is both tempting and mortgage fraud.
Worked example: $350,000 rental with 25% down at 7.125%
You buy a single-family rental for $350,000 with 25% down, financed over thirty years at 7.125%. Property tax after reassessment is $4,400, a landlord policy costs $2,000, and there are no HOA dues.
- Down payment. 350,000 × 0.25 = $87,500.
- Loan amount. 350,000 − 87,500 = $262,500, a 75% loan-to-value.
- Monthly rate. 0.07125 ÷ 12 = 0.0059375.
- Payments. n = 30 × 12 = 360.
- Principal and interest. M = 262,500 × 0.0059375 ÷ (1 − 1.0059375−360) = 1,558.59 ÷ 0.881303 = $1,768.51 a month.
- Escrow. 4,400 ÷ 12 = $366.67 of tax, plus 2,000 ÷ 12 = $166.67 of insurance = $533.34.
- Total monthly payment. 1,768.51 + 533.34 = $2,301.85.
- First month's split. Interest is 262,500 × 0.0059375 = $1,558.59, so only $209.92 of that first payment reduces the balance — 11.9% of the principal-and-interest portion.
- Total interest over the full term. 1,768.51 × 360 − 262,500 = 636,664 − 262,500 = $374,164.
Step 8 is the one that reframes the deal. Almost 88% of your first payment is rent on the money. That share falls every month, but it takes until roughly month 240 of a 7.125% thirty-year loan before principal and interest are split evenly — which is why the principal-paydown component of a rental's return starts small and grows.
Turning the payment into a decision
The payment on its own tells you nothing about whether the property works. Three comparisons make it useful.
Against net operating income. Divide NOI by annual debt service and you have the debt service coverage ratio. On the worked example, annual principal and interest is $21,222. If the property produces $26,500 of NOI, coverage is 1.25 — the level most dedicated investor lenders want. Build NOI properly with the NOI calculator, and note that the coverage test uses principal and interest only, while taxes and insurance sit inside NOI as operating expenses.
Against the cap rate. Annual debt service divided by the original loan is the loan constant: 21,222 ÷ 262,500 = 8.08%. Compare that to the property's cap rate. Above it, borrowing reduces your cash-on-cash return relative to paying cash; below it, borrowing raises it. That single comparison is the cleanest test of whether the leverage on a deal is working for you.
Against the alternative down payments. More money down cuts the payment and usually the rate too, but it also raises the capital you are committing. The right amount is not the largest you can afford — it is the one that produces the return you want at a coverage ratio you can survive. Test it with the cash-on-cash return calculator.
Monthly principal and interest per $1,000 borrowed
| Rate | 30 years | 20 years | 15 years |
|---|---|---|---|
| 6.000% | $5.9955 | $7.1643 | $8.4386 |
| 6.500% | $6.3207 | $7.4557 | $8.7111 |
| 7.000% | $6.6530 | $7.7530 | $8.9883 |
| 7.125% | $6.7372 | $7.8282 | $9.0583 |
| 7.500% | $6.9921 | $8.0559 | $9.2701 |
| 8.000% | $7.3376 | $8.3644 | $9.5565 |
| 8.500% | $7.6891 | $8.6782 | $9.8474 |
Each factor is 1,000 × r ÷ (1 − (1+r)^−n) at that rate and term. The gap between 6.500% and 7.125% on the 30-year column is $0.4165 per $1,000 per month, which is the $109.33 investor premium on a $262,500 loan.
Occupancy is a representation you sign
Every mortgage application states how you will occupy the property, and the note and security instrument contain an occupancy covenant. Stating that a property will be your primary residence to obtain the lower rate and smaller down payment, when you intend to rent it out, is occupancy fraud — a federal crime, and grounds for the lender to call the loan due. The rate difference is real and it is meant to be. If circumstances genuinely change after closing, that is a different matter; tell the servicer.
Costs this payment does not include
- Vacancy and turnover. The payment is due in the months no tenant is paying. Model it in the cash-flow calculation, not here.
- Management. Typically a percentage of collected rent, plus a leasing fee for each new tenancy.
- Repairs and capital reserves. Roofs, HVAC and appliances are not in the mortgage payment and are entirely in your budget.
- Closing costs and reserves. Points, title, appraisal and required liquid reserves are cash on top of the down payment. Size them with the closing costs calculator.
- Rising escrow. The tax bill reassesses on purchase in many jurisdictions, and landlord insurance premiums have moved sharply in exposed markets. Both change the payment after closing.
- Umbrella liability cover. Not required by the lender, and normal practice for landlords.
Conventional, portfolio, DSCR and commercial
Four financing routes exist for a small rental, and the payment formula is the same in each — what changes is how you qualify and how the loan is structured.
Conventional agency financing is the cheapest and the most restrictive. You qualify on your personal debt-to-income, the property must meet guidelines, and there is a limit on how many financed properties you may own. Test your personal ratios with the home affordability calculator.
DSCR loans qualify on the property's coverage ratio rather than your income, which is what makes them useful once agency limits bind. They price above conventional and often carry prepayment penalties. The DSCR calculator is where you check whether a property clears the threshold.
Portfolio loans from a local bank stay on the lender's books, so guidelines are negotiable. Expect shorter terms — often a five-year balloon on a twenty-to-twenty-five-year amortisation — which introduces refinance risk that a thirty-year fixed does not have.
Commercial loans apply to five-plus unit properties, and they change the whole analysis: shorter terms, balloon maturities, coverage-based sizing and often recourse carve-outs rather than full personal liability.
One structural feature is worth naming. On a fixed-rate loan the largest expense in the rental is fixed in nominal dollars for thirty years while rents, taxes, insurance and repairs drift upward. That asymmetry is the strongest argument for long fixed-rate debt on a buy-and-hold, and it is exactly what a balloon-term portfolio loan gives up.