Commercial Mortgage Loan Calculator
Planning to buy or refinance an investment property? Our free mortgage loan calculator estimates your monthly payment, total interest and loan balance over time, complete with a full amortization schedule. Enter the purchase price, down payment, interest rate and term below to see how different financing scenarios compare.
| Payment # | Date | Type | Payment | Principal | Interest | Balance |
|---|---|---|---|---|---|---|
| Enter loan details above to see the amortization schedule | ||||||
Mortgage Calculator — User Guide
The NAI Long Island Mortgage Calculator is designed for commercial real estate professionals. It computes monthly payments, interest-only periods, balloon payoffs, and generates a full amortization schedule — with paginated on-screen viewing, Excel export, and a print/PDF function.
| Field | Description | Example |
|---|---|---|
| Loan Amount | The total principal to be borrowed. Enter the net loan amount, not the purchase price. | $2,500,000 |
| Interest Rate | Annual interest rate (%). Supports increments of 0.125% to match commercial lending conventions. | 6.875% |
| Amortization Period | The number of years used to calculate the monthly principal & interest payment. This is the full repayment schedule, independent of when the loan comes due. | 25 years |
| Field | Description | Example |
|---|---|---|
| Loan Term | How long the loan is in place before it matures. If the loan term is shorter than the amortization period, a Balloon payment will appear at maturity. | 10 years |
| Interest Only Period OPTIONAL | The number of years at the start of the loan during which only interest is paid — no principal reduction occurs. After this period, the remaining balance is amortized over the remaining amortization schedule. | 2 years |
| Start Date | The month and year of the first payment. Used to populate the Date column in the amortization schedule. Defaults to the current month if left blank. | Jan 2025 |
The results bar updates automatically as you type. The four result boxes change depending on whether an interest-only period or balloon payment is present:
| Scenario | Box 1 | Box 2 | Box 3 | Box 4 |
|---|---|---|---|---|
| Standard P&I (no I/O, no balloon) |
Monthly Payment | Total Principal | Total Interest | Total Payment |
| With Interest-Only Period | I/O Monthly Pmt | P&I Monthly Pmt | Total Interest | Total Payment |
| With Balloon Payment | Monthly Payment | Total Principal | Total Interest | Balloon Payment |
| I/O + Balloon | I/O Monthly Pmt | P&I Monthly Pmt | Total Interest | Balloon Payment |
The schedule shows every payment across the full loan term. Each row is color-coded by type:
| Column | Description |
|---|---|
| Payment # | Sequential payment number (1 = first month). Balloon row shows "—". |
| Date | Month and year of the payment, based on the Start Date. |
| Type | I/O, P&I, or Balloon — see badges above. |
| Payment | Total amount due that month (interest + principal for P&I rows). |
| Principal | The portion of the payment applied to reduce the outstanding balance. Shows "—" during interest-only months. |
| Interest | The portion of the payment that is interest cost for that month. |
| Balance | Remaining principal balance after the payment is applied. |
The schedule displays 12 rows per page. Use the First / Prev / Next / Last buttons to navigate. The Page Subtotals row at the bottom of each page sums the Payment, Principal, and Interest columns for the visible rows.
| Button | What It Does |
|---|---|
| Reset | Clears all input fields and resets the results and schedule to their initial empty state. |
| Download Excel | Exports the full amortization schedule (all pages) to a formatted .xlsx file named NAI-Mortgage-Amortization-Schedule.xlsx. The file includes loan parameter details in the header rows, followed by every payment row. Requires a calculated schedule — enter loan details first. |
| Print / Save PDF | Opens a print-ready popup window containing the complete (unpaginated) schedule. Use your browser's Print command (Ctrl+P / Cmd+P) and select Save as PDF to create a PDF. The printout is formatted in landscape orientation. Allow browser popups for this page if prompted. |
For loans with no interest-only period, the fixed monthly payment is calculated using the standard mortgage formula:
Where P = Loan Amount, r = Monthly Interest Rate (Annual Rate ÷ 12), n = Total Amortization Months.
During the interest-only period, each monthly payment equals:
The principal balance does not decrease during this period. After the I/O period ends, the P&I payment is recalculated based on the original principal over the remaining amortization months (Amortization Period minus I/O Period).
When the Loan Term is shorter than the Amortization Period, the loan does not fully amortize by maturity. The remaining outstanding balance at the end of the loan term is the balloon payment. The calculator adds a final Balloon row to the schedule showing this amount.
| Setting | Controls |
|---|---|
| Amortization Period | How the monthly P&I payment is sized (determines payment amount) |
| Loan Term | How long until the loan matures (determines when the balloon is due) |
Example: A $3M loan at 7%, 25-year amortization, 10-year term — the payment is sized as if it will amortize over 25 years, but at year 10 the remaining balance (~$2.3M) is due as a balloon.
| Scenario | Loan Amount | Rate | Amort | Term | I/O Period |
|---|---|---|---|---|---|
| Fully amortizing Traditional loan that pays off at maturity |
$2,000,000 | 6.5% | 20 yrs | 20 yrs | None |
| Balloon loan Common in commercial CRE lending |
$2,000,000 | 6.5% | 25 yrs | 10 yrs | None |
| I/O then P&I Bridge or construction-to-perm |
$2,000,000 | 7.0% | 25 yrs | 10 yrs | 2 yrs |
| Full-term I/O Interest only for entire loan term (balloon = full principal) |
$2,000,000 | 7.0% | 25 yrs | 5 yrs | 5 yrs |
How to Use the Mortgage Loan Calculator
- Loan amount: Enter the purchase price and down payment, or the amount you plan to borrow. Commercial lenders commonly require a larger down payment than residential lenders.
- Interest rate: Use a rate quoted by your lender, or test several rates to see how changes affect your payment.
- Term and amortization: Commercial loans often have a shorter term than the amortization period, which can leave a balloon payment due at maturity.
- Review the schedule: The amortization schedule shows how each payment is divided between principal and interest, and how the balance declines over time.
Understanding Commercial Mortgage Terms
Commercial real estate loans work differently from home mortgages. Lenders focus heavily on the property’s income and the borrower’s experience, not just personal credit. Two ratios come up in almost every deal. The loan-to-value ratio compares the loan amount to the property’s appraised value, and the debt service coverage ratio compares the property’s net operating income to its annual loan payments. A mortgage loan calculator helps you estimate the annual debt service so you can check whether a deal meets a lender’s coverage requirements.
Many commercial loans are structured with a term of five, seven or ten years and an amortization of twenty to thirty years. Because the loan matures before it is fully paid off, borrowers typically refinance or sell before the balloon payment is due. Prepayment penalties, yield maintenance or defeasance provisions may also apply, so review the loan documents carefully with your attorney and lender.
Tips for Financing an Investment Property
Run several scenarios with the mortgage loan calculator before you make an offer. Compare a higher down payment with a lower one, or a fixed rate with a shorter term, to understand how each choice affects cash flow. Remember to budget for closing costs, reserves, property taxes, insurance and capital improvements, which are not included in the monthly principal and interest payment.
Fixed vs. Variable Rates
Fixed-rate loans keep the interest rate the same for the full term, which makes cash flow predictable and simplifies budgeting. Variable-rate loans are tied to a benchmark index and can start lower, but payments may rise if rates increase. Some borrowers choose a hybrid structure or purchase an interest rate cap to limit their exposure. When comparing options in the mortgage loan calculator, model the payment at today’s rate and at a higher rate to see how much cushion the property’s income provides, and consider how long you expect to hold the investment.
Talk to a Capital Markets Advisor
Our capital markets team helps investors buy, sell and finance commercial properties across Long Island. We can connect you with lenders, help evaluate financing options and analyze how a property’s income supports the debt. Contact NAI Long Island to discuss your next acquisition, or try our CRE financial modeling and valuation app. As a member of NAI Global, we also work with investors and lenders nationwide.
This mortgage loan calculator provides estimates for planning purposes only and does not represent a loan offer. Actual rates, terms and payments are determined by your lender.