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Property Rent, Vacancy & Operating Income

Estimate a property’s operating income from rented area, occupancy, other income and itemized operating costs.

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Calculator inputs

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How to use this calculator

  1. Enter the known values in the units shown. Results update as you type.
  2. Where results are editable, change one to solve backwards. Lock a value to hold it fixed.
  3. Use the worked example to check the method. Reset restores the starting fields.

Use the result with context

Results are estimates for planning and education. Confirm rates, taxes, fees, and legal requirements with the relevant institution or a qualified professional before making a financial decision.

Formula and method

A 100 m² property at 20 per m² for the reporting period has potential rent of 2,000. At 90% occupancy, plus 100 other income and 800 expenses, NOI is 1,100.

Effective income = area × rent per area × occupancy + other income; NOI = effective income − operating expenses

Worked example

Enter these known values and leave the other values blank.

Rentable area
100 m²
Rent per selected area for the period
20 USD / m²
Occupancy
90 %
Other income for the same period
100 USD
Net property-tax expense
200 USD
Property management fees
150 USD
Insurance
100 USD
Repair
50 USD
Maintenance
100 USD
Other operating expenses
200 USD
Potential gross income
2100 USD
Vacancy loss
200 USD
Effective gross income
1900 USD
Operating expenses
800 USD
Net operating income for the period
1100 USD

Assumptions and limitations

  • Use one reporting period for rent, other income and every expense. The calculator does not infer whether the amounts are monthly or annual.
  • Vacancy reduces the modeled area-based rental income only. Other income is added separately and is not multiplied by occupancy.
  • Occupancy ranges from 0% to 100%. Area and rent per area must be positive. NOI may be negative when operating expenses exceed effective income.
  • Debt principal, financing interest, depreciation and capital expenditures are not ordinary property operating expenses in this NOI model. Use the accounting definition applicable to your analysis.
  • Property tax is a net expense input, so a signed credit or refund can be represented. Total operating expenses must remain nonnegative. Other listed expense inputs are nonnegative.

Common questions

Do I enter mortgage payments as an operating expense?

This NOI measure is before debt service. Adding principal or financing-interest payments would produce a different cash-flow measure.

Does vacancy affect all income automatically?

No. The vacancy loss applies only to area multiplied by rent per area. Enter any expected change to other income in that separate field.

References

The calculation equations, inverse formulas, units, and input rules were imported from this source. Bookify provides the interface and equation solver.

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