Commercial Mortgage Calculator - Free Online Tool

Calculate commercial loan payments, loan sizing, DSCR, and full amortization schedules

A commercial mortgage calculator is an essential tool for anyone involved in commercial real estate (CRE) financing. Whether you are purchasing an office building, investing in a multifamily apartment complex, acquiring industrial warehouse space, or refinancing an existing commercial property, understanding the precise payment structure, debt service requirements, and lender qualification metrics is critical to making sound investment decisions. This free commercial mortgage calculator provides both payment analysis and loan sizing in a single comprehensive tool. Commercial mortgages differ fundamentally from residential home loans in several important ways. First, commercial loans almost always feature a shorter loan term than the amortization period. For example, a commercial mortgage might amortize over 25 years but have a 10-year maturity, creating a balloon payment — a large lump sum due at the end of the loan term representing the remaining unpaid principal. Understanding the size of this balloon payment is critical for refinancing planning. Second, commercial lenders evaluate loans primarily through the lens of the property's income-generating capacity, not the borrower's personal income. The debt service coverage ratio (DSCR), which measures how many times the property's net operating income (NOI) covers the annual mortgage payment, is the single most important underwriting metric in commercial lending. This calculator operates in two distinct modes. The Payment Calculator mode takes your loan amount, interest rate, amortization period, and loan term as inputs and produces the monthly principal and interest payment, interest-only payment, balloon payment amount, total interest over the loan life, and a complete month-by-month amortization schedule. You can also input the property's NOI to see the resulting DSCR, enter the purchase price for LTV analysis, add origination fees for true APR calculation, and model extra monthly payments to see interest savings. The Loan Sizing mode works in reverse — instead of starting with a loan amount, you start with the property's net operating income and let the calculator determine the maximum loan the property can support. This mode uses the "lesser of three methods" approach that mirrors actual commercial lender underwriting. It computes the maximum loan based on loan-to-value (LTV) constraints, DSCR requirements, and debt yield minimums, then takes the smallest of the three as the maximum supportable loan amount. This is exactly how institutional lenders like life insurance companies, CMBS conduits, and agency lenders (Fannie Mae and Freddie Mac) size commercial loans. The calculator also includes property type and loan type selectors that automatically suggest typical LTV maximums, DSCR minimums, and amortization/term presets based on industry benchmarks. For instance, multifamily properties typically qualify for higher LTV ratios (75–80%) compared to hotels (60–70%), reflecting the different risk profiles. Similarly, SBA 504 loans typically offer 25-year fully amortizing terms, while conventional bank loans commonly feature 7–10 year terms with 25-year amortization. Every calculation generates a full amortization schedule with annual summaries and monthly detail, which you can export to CSV for use in Excel or financial modeling. The visual charts — including a principal vs. interest donut chart, balance decay line graph, and DSCR bullet chart — make it easy to communicate financing scenarios to partners, lenders, or investment committees. Whether you are a commercial real estate broker, property investor, developer, or business owner seeking owner-occupied commercial space, this calculator gives you the analytical depth that commercial lending requires.

Understanding Commercial Mortgages

What Is a Commercial Mortgage?

A commercial mortgage is a loan secured by commercial property — any real estate used for business purposes rather than residential housing. This includes office buildings, retail shopping centers, industrial warehouses, multifamily apartment buildings with five or more units, hotels, self-storage facilities, and mixed-use properties. Unlike residential mortgages that are underwritten primarily based on the borrower's personal income and credit, commercial mortgages are underwritten based on the income the property itself generates. Lenders evaluate the property's net operating income (NOI), the loan-to-value ratio, and the debt service coverage ratio to determine both the maximum loan amount and the interest rate. Commercial mortgage terms typically range from 5 to 25 years, with amortization periods of 20 to 30 years, creating a balloon payment structure where the remaining balance is due at maturity.

How Are Commercial Mortgage Payments Calculated?

Commercial mortgage payments use the standard amortization formula: PMT = P × r × (1+r)^n / ((1+r)^n − 1), where P is the principal loan amount, r is the periodic interest rate (annual rate divided by 12 for monthly payments), and n is the total number of amortization periods in months. The key distinction in commercial lending is that while payments are calculated using the full amortization period (e.g., 25 years = 300 months), the loan matures much sooner (e.g., 10 years = 120 months). At maturity, the remaining unpaid balance — the balloon payment — becomes due. This is calculated as the outstanding balance on the amortization schedule at the maturity date. For interest-only periods, the payment is simply the loan balance multiplied by the monthly interest rate, with no principal reduction occurring.

Why Does Commercial Mortgage Analysis Matter?

Commercial mortgage analysis is critical because the stakes are significantly higher than residential lending — commercial properties typically involve millions of dollars in financing, and the wrong loan structure can destroy an otherwise profitable investment. The DSCR tells you whether the property generates enough income to comfortably cover the mortgage payment; most lenders require a minimum DSCR of 1.20x to 1.30x, meaning the property must generate 20–30% more income than the debt payment. The LTV ratio determines how much equity you need to bring; typical maximums range from 65% to 80% depending on property type. Understanding the balloon payment is essential for refinancing planning — if property values decline or interest rates rise before maturity, refinancing the balloon can become difficult or impossible, a situation known as maturity default risk. Modeling these scenarios in advance with a commercial mortgage calculator is fundamental due diligence.

Limitations and Assumptions

This calculator models fixed-rate commercial mortgages with level payments during the amortization period. It does not account for adjustable-rate commercial loans where the rate resets periodically, construction loan draws and interest reserves, participation or mezzanine financing structures, or prepayment penalties (defeasance, yield maintenance, or step-down penalties) that are common in CMBS and life company loans. The DSCR calculation uses trailing or underwritten NOI as a single static figure; actual lender underwriting may apply haircuts, vacancy adjustments, or management fee loading. Property appreciation projections use a simple compound growth model and do not account for capital expenditure cycles, market corrections, or lease rollover risk. Always verify calculations with your commercial mortgage broker or lender, as actual terms will depend on property condition, market, sponsorship, and current lending standards.

Formulas

Monthly P&I Payment

PMT = P × r × (1+r)^n / ((1+r)^n − 1)

Where P is principal, r is monthly rate (annual rate / 12 / 100), and n is total amortization months.

Balloon Payment

Balloon = P × (1+r)^t − PMT × ((1+r)^t − 1) / r

Remaining balance after t months of payments, where t is the loan term in months.

DSCR

DSCR = NOI / (PMT × 12)

Net Operating Income divided by Annual Debt Service. Lenders typically require 1.20x–1.30x minimum.

LTV Ratio

LTV = Loan Amount / Property Value × 100

Loan-to-Value ratio. Commercial lenders typically cap at 65–80% depending on property type.

Debt Yield

Debt Yield = NOI / Loan Amount × 100

Rate-independent measure of loan risk. Most lenders require a minimum of 8–12%.

Max Loan (DSCR Method)

Max Loan = PV(r, n, NOI / min_DSCR / 12)

Present value of maximum allowable debt service payments, constrained by minimum DSCR.

Reference Tables

Typical Max LTV by Property Type

Maximum loan-to-value ratios accepted by most commercial lenders, varying by property type and risk profile.

Property Type	Typical Max LTV
Multifamily	75–80%
Office	65–75%
Retail	65–75%
Industrial	70–75%
Hotel / Hospitality	60–70%
Self-Storage	65–75%
Mixed-Use	65–75%

Minimum DSCR by Lender Type

Minimum debt service coverage ratios required by different types of commercial mortgage lenders.

Lender Type	Minimum DSCR
Life Insurance Company	1.25–1.30x
CMBS	1.20–1.25x
Fannie Mae / Freddie Mac	1.25x
HUD / FHA	1.17–1.20x
Regional Bank	1.20–1.35x
SBA 7(a) / 504	1.25x
Bridge / Debt Fund	1.05–1.20x

Typical Commercial Loan Terms

Common loan term and amortization periods for different commercial mortgage types.

Loan Type	Typical Term	Typical Amortization
Conventional Bank	5–10 years	20–25 years
CMBS	10 years	25–30 years
Life Company	10–25 years	25–30 years
SBA 7(a)	10–25 years	10–25 years
SBA 504	20–25 years	20–25 years
Bridge	1–3 years	IO or 25–30 years
Fannie / Freddie	5–10 years	30 years

Worked Examples

Standard Commercial Mortgage Payment

$1,000,000 loan at 6.5% interest, 25-year amortization, 10-year term

Monthly rate: 6.5% / 12 / 100 = 0.005417

Total amortization months: 25 × 12 = 300

Monthly P&I: $1,000,000 × 0.005417 × (1.005417)^300 / ((1.005417)^300 − 1) = $6,752.79

After 120 payments (10 years), remaining balance = $743,413 (balloon payment)

Total interest over 10 years: $553,748

Monthly payment of $6,752.79 with a $743,413 balloon payment due at the end of year 10.

Three-Method Loan Sizing

NOI: $150,000, Cap Rate: 7%, Max LTV: 75%, Min DSCR: 1.25x, Min Debt Yield: 10%, Rate: 6.5%, 25-year amortization

Property Value = $150,000 / 0.07 = $2,142,857

LTV Method: $2,142,857 × 75% = $1,607,143

DSCR Method: Allowable annual DS = $150,000 / 1.25 = $120,000 → PV = $1,479,822

Debt Yield Method: $150,000 / 10% = $1,500,000

Binding constraint: DSCR Method (smallest value)

Maximum supportable loan of $1,479,822 constrained by the DSCR method. Monthly payment on this amount would be $9,997.

How to Use

Select your calculator mode

Choose Payment Calculator to analyze a specific loan amount, or Loan Sizing to determine the maximum loan a property can support based on its income and lender requirements.

Enter property and loan details

Select the property type and loan type for benchmark guidance. Enter the loan amount, interest rate, amortization period, and loan term. If the term is shorter than the amortization, a balloon payment will be calculated automatically.

Add optional inputs for deeper analysis

Enter the property's NOI for DSCR calculation, purchase price for LTV analysis, origination fees for true APR, and an appreciation rate for equity forecasting at balloon maturity. Use the Advanced Options to add extra monthly payments and see interest savings.

Review results and export

Examine the monthly payment, balloon amount, DSCR, LTV, and full amortization schedule. Use the line graph and donut chart to visualize the loan. Export the schedule to CSV, print the results, or share via clipboard.

Frequently Asked Questions

What is a balloon payment in a commercial mortgage?

A balloon payment is the remaining unpaid principal balance that becomes due at the end of the loan term when the term is shorter than the amortization period. For example, if you have a $1,000,000 loan amortized over 25 years but with a 10-year term, the monthly payments are calculated as if you will pay over 25 years, but after 10 years of payments, the remaining balance — often 60–70% of the original loan — is due as a single lump sum. Borrowers typically refinance the balloon payment with a new loan, sell the property, or pay it off from other funds. Balloon structures are standard in commercial lending because they allow lenders to reprice loans periodically to reflect changing market interest rates while giving borrowers the benefit of lower monthly payments based on longer amortization.

What is DSCR and why does it matter for commercial loans?

DSCR stands for Debt Service Coverage Ratio and is the most important underwriting metric in commercial mortgage lending. It is calculated as the property's annual Net Operating Income (NOI) divided by the annual debt service (total mortgage payments for the year). A DSCR of 1.25x means the property generates 25% more income than needed to cover the mortgage payment. Most commercial lenders require a minimum DSCR between 1.20x and 1.30x, depending on the lender type and property type. A DSCR below 1.0x means the property does not generate enough income to cover the mortgage, which is a red flag for any lender. Higher DSCRs indicate more cushion and lower risk, which can result in better interest rates and terms.

How does the three-method loan sizing work?

The three-method loan sizing approach mirrors how institutional commercial lenders actually underwrite loans. It calculates the maximum loan amount using three independent constraints: the LTV method (property value times maximum LTV percentage), the DSCR method (the present value of the maximum allowable debt service payments based on the required minimum DSCR), and the Debt Yield method (NOI divided by the minimum required debt yield percentage). The maximum supportable loan is the smallest of the three results — this is called the 'binding constraint' and represents the most conservative limit. This approach ensures the loan meets all three underwriting criteria simultaneously, which is exactly how lenders like life insurance companies, CMBS conduits, and agency lenders determine loan amounts.

What is the difference between loan term and amortization period?

The amortization period is the time frame used to calculate the payment amount — typically 20 to 30 years for commercial loans. The loan term (or maturity) is how long the loan actually lasts before the full remaining balance is due. In commercial lending, the term is almost always shorter than the amortization. For example, a loan with a 25-year amortization and a 10-year term means payments are calculated as if you have 25 years to pay, making them lower and more manageable. However, after 10 years, whatever balance remains must be paid off — this is the balloon payment. When the term equals the amortization, the loan is 'fully amortizing' and no balloon payment exists, which is common only in SBA loans.

How does the interest-only period affect my commercial mortgage?

An interest-only (IO) period allows you to pay only the interest on the loan for a set number of years before principal amortization begins. During the IO period, your monthly payment is significantly lower because you are not reducing the principal balance. For a $1,000,000 loan at 6.5%, the interest-only payment is approximately $5,417 per month compared to about $6,753 for a fully amortizing P&I payment over 25 years — a savings of $1,336 per month. However, the trade-off is that no principal is paid down during the IO period, so the remaining amortization payments will be higher (calculated over a shorter remaining period), and the balloon payment at maturity will be larger. IO periods of 1–3 years are common in CMBS and bridge loans.

What is debt yield and how is it used in commercial lending?

Debt yield is calculated as the property's annual Net Operating Income divided by the loan amount, expressed as a percentage. For example, if a property generates $150,000 in NOI and the loan amount is $1,500,000, the debt yield is 10%. Debt yield has become increasingly important in commercial mortgage underwriting, particularly for CMBS lenders, because it is independent of the interest rate and amortization period — unlike DSCR, which changes when rates change. A higher debt yield indicates lower risk because the property generates more income relative to the loan. Most lenders require a minimum debt yield of 8–12%, with 10% being a common threshold. In the three-method loan sizing approach, the debt yield constraint often becomes the binding constraint when property values are high relative to income.