Commercial Mortgage Calculator: DSCR and Maximum Loan

By the Ottawa Mortgages editorial team · Last reviewed: September 2026 · How we write our guides

What is DSCR? The debt service coverage ratio compares a property’s net operating income (NOI) to its annual loan payments. A DSCR of 1.25x means the property earns 25% more than the payments require. Most commercial lenders set a minimum DSCR, often around 1.2x to 1.3x, and the maximum loan is the lower of the DSCR limit and the loan-to-value limit.
Your estimated debt service coverage ratio
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Estimate only. Lenders calculate net operating income, rates and required ratios differently.

How to use this calculator

  1. Enter the property’s net operating income: rents and other income, minus vacancy and operating expenses, before mortgage payments.
  2. Enter the purchase price or appraised value and the loan-to-value you expect.
  3. Enter a rate and amortization. Canadian mortgages use semi-annual compounding, and this calculator does too.
  4. Choose the DSCR your lender requires. The tool shows whether your loan meets it and the estimated maximum loan.

How DSCR is calculated

DSCR = Net operating income ÷ Annual debt service. If your NOI is $150,000 and your annual loan payments total $120,000, your DSCR is 1.25x. If the payments were $150,000, the DSCR would be 1.00x, meaning no cushion at all.

What raises your maximum loan

  • Higher net operating income, through higher rents, lower vacancy or lower expenses
  • A longer amortization, which lowers annual payments
  • A lower interest rate
  • A lender with a lower DSCR requirement, such as for certain insured programs

Related guides

Frequently asked questions

Do lenders use my personal income for a commercial mortgage?

They also look at your finances and often want a personal guarantee, but the property’s income is the main test for investment properties.

What expenses are included in NOI?

Operating costs such as property taxes, insurance, utilities, maintenance, management and a vacancy allowance. Mortgage payments and income tax are not included.

Why is my result different from a lender’s?

Lenders adjust income and expenses, use their own rates and stress tests, and may apply different DSCR rules by property type.

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