Is mortgage principal an expense?

It reduces monthly cash flow but also builds equity. This calculator focuses on cash leaving the account.

Why include a vacancy allowance?

Even well-run rentals can have turnover or unpaid periods, so assuming every unit is occupied forever can overstate cash flow.

REAL ESTATE

Rental Property Cash Flow Calculator

Calculate monthly rental property cash flow after mortgage, vacancy, management, maintenance, taxes, insurance, and utilities.

Monthly cash flow-$60After loan, tax, insurance, vacancy, and upkeep

Before reserves$200Rent minus principal, interest, taxes, and insurance

Reserves$260Maintenance, vacancy, and property management

THE MONTH

What the rent keeps.

The rent does not cover the loan and the reserves.

Line	Monthly
Rent	$1,300
Principal and interest	$800
Taxes and insurance	$300
Maintenance	$65
Vacancy	$65
Property management	$130
HOA, utilities, exterior	$0
Cash flow	-$60

How the reserves are estimated

Percent of rent. Newly updated includes structure, appliances, and systems. Average is compared with homes of a similar age. Vacancy is 5% for a single-family home and 10% for a multi-unit or college rental. Property management is 10%.
Age	Newly updated	Some updating	Average
0–10 years	5%	10%	15%
10–50 years	10%	15%	20%
50+ years	15%	20%	25%

THE PROPERTY

Rent, the loan, and the building.

Monthly rent

Principal and interestMonthly taxesMonthly insuranceHOAUtilitiesExterior care

Property ageConditionProperty type

How rental cash flow is estimated

Start with monthly rent and subtract a vacancy allowance.
Estimate management and maintenance reserves from the selected property assumptions.
Subtract mortgage, tax, insurance, utilities, and other monthly costs.
Compare effective rental income with all modeled expenses.

Worked example

If a property collects $2,000 monthly after vacancy and modeled expenses total $1,650, estimated cash flow is $350 per month before income tax and major unplanned costs.

Assumptions and boundaries

Vacancy, management, and maintenance use the displayed planning rates.
Annual tax and insurance entries are divided evenly by month.
The calculation represents a stabilized month rather than lease-up timing.

Important limitation: Actual results can change with repairs, capital expenditures, tenant turnover, local law, taxes, financing terms, and unpaid rent. Keep a separate reserve and verify local costs.

Sources and review

Methodology and links reviewed September 22, 2026. This educational estimate is not financial, tax, legal, investment, or lending advice.

IRS Publication 527, Residential Rental Property

Frequently asked questions

Is mortgage principal an expense?: It reduces monthly cash flow but also builds equity. This calculator focuses on cash leaving the account.
Why include a vacancy allowance?: Even well-run rentals can have turnover or unpaid periods, so assuming every unit is occupied forever can overstate cash flow.