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How to Use the Rental Underwriting Worksheet

Build a transparent one-month rental underwriting scenario from the price, cash invested, income, expenses, vacancy, and debt-service assumptions you enter.

August 3, 2026by Useful Tools Editorial TeamTutorials

What the worksheet calculates

The Rental Analyzer is a one-month underwriting worksheet. From your entered assumptions it shows effective income after vacancy, operating expenses, net operating income (NOI), monthly cash flow after debt service, cap rate, and cash-on-cash return. It does not calculate a mortgage payment, future appreciation, selling costs, taxes, financing eligibility, or a market rent estimate.

Enter a defensible scenario

  1. Enter the purchase price and the initial cash invested. Initial cash invested is your own all-in cash assumption, such as down payment plus costs and repairs; the tool does not derive it.
  2. Enter monthly rent and any other monthly income. Use comparable, currently achievable rents rather than an aspirational figure.
  3. Enter a vacancy percentage. The worksheet reduces gross income by that percentage before calculating NOI.
  4. Enter every monthly operating expense you expect: property tax, insurance, repairs, management, utilities, HOA, and other expenses. Use 0 only for a genuinely inapplicable category.
  5. Enter the monthly debt service from a lender quote or your separate Mortgage Calculator scenario.

Read the results in the right order

NOI is effective rental income minus operating expenses; it intentionally excludes debt service. Monthly cash flow then subtracts the debt-service amount you entered. Cap rate uses annual NOI divided by purchase price. Cash-on-cash return uses annual cash flow divided by the initial cash invested you entered.

Run a downside case as well as a base case: lower rent, higher vacancy, and realistic repair or management allowances. A result is only a model of its assumptions and should not replace an inspection, appraisal, lender review, or local legal and tax advice.

Related tools: Property Tax Worksheet, Cash-to-Close Worksheet, and Loan Payoff Calculator.

Further reading

Tutorials references and next steps

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