# Net Operating Income Calculator

> Net operating income calculator: compute real estate NOI from rental income and operating expenses with the standard NOI formula. Free, editable inputs.

- **Canonical URL:** https://boringtoolskit.com/net-operating-income-calculator/
- **Category:** Finance & Investing
- **Evidence level:** authored-methodology
- **Reviewed:** 2026-09-20
- **Last verified:** 2026-10-12
- **Privacy:** Inputs and results stay in this browser unless the page clearly labels an external request.

## How it works

NOI = gross operating income − operating expenses. The calculator sums your rental income and other income, then subtracts five annual expense lines: maintenance, property management, and utilities & insurance (plus property taxes if entered there).

## Worked example

A small duplex rents for $28,800/yr with $2,400/yr laundry income. Expenses: $3,600 maintenance, $2,880 management, $1,800 utilities & insurance. NOI = $31,200 − $12,480 = $18,720/yr — a 60% operating margin.

## Assumptions

- All figures are annual; the tool does not convert monthly inputs.
- Expense lines are summed as entered — the labels group common costs but any operating expense can go in any line.
- Debt service, income taxes, and capital expenditures are outside NOI by definition and are not inputs.

## Common questions

### Is NOI the same as profit?

No. NOI comes before mortgage payments, income taxes, depreciation, and capital expenditures. Your taxable profit and bank balance can both differ substantially from NOI.

### Do I enter monthly or yearly numbers?

Yearly. The result is an annual NOI figure — multiply a monthly rent by 12 before entering it, and use annual amounts for every expense line.

### Where do property taxes go?

Enter them in the Utilities & insurance line (or Maintenance if you prefer) — the calculator sums every expense field you fill, so the total is what matters.

### What is a good operating margin?

Residential rentals commonly run 55–70% before debt service; properties with high management or utility costs run lower. A sudden margin drop usually signals a maintenance spike or rising expenses, not a market shift.

### Can NOI be negative?

Yes — a heavily vacant or mismanaged property can spend more than it collects. Negative NOI means the property costs you money every month even before the loan.

### How does NOI relate to cap rate?

Cap rate is NOI divided by what the property costs or is worth. It converts NOI into a comparable return across properties, like a yield.

### Why doesn't the calculator have a vacancy field?

To keep the tool to five lines. Vacancy is an estimate about the future; folding your realistic collected rent into the income fields gives the same NOI as a vacancy-adjusted worksheet.

## Related tools

- /cap-rate-calculator/
- /rental-property-roi-calculator/
- /50-30-20-budget-calculator/

## Sources

- [Calculator methodology and reference cases](https://boringtoolskit.com/methodology/)
- [Net operating income](https://en.wikipedia.org/wiki/Net_operating_income)

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