Rental Property ROI Calculator
Note: This post is a little different from our usual dog-related content.
We built this simple calculator to help us quickly estimate rental property returns.
It's mainly for our personal use, but we're sharing it here in case it might be useful for someone else.
Enter Your Property Inputs
How This Calculator Works
Purpose: This calculator provides a realistic estimate for comparison across
properties and scenarios.
It is not a guarantee of future performance.
Monthly cash flow: We estimate it as rent minus mortgage plus operating expenses, then
annualize it to show cash-on-cash ROI using your down payment as invested cash.
Vacancy: The default value is set to 0.6 months. While a new house may
experience 1 to 2 months of vacancy initially, we use 0.6 as a long-term assumption because, on average,
tenants stay for more than three years.
Maintenance and repair: The default cost is set at $182 per month. While some months may
have no expenses at all, there are times when unexpected repairs can cost several thousand dollars in a
single month. This $182 figure is based on data from the book
Rental Property Investing
.
Mortgage: It is calculated with the standard amortization formula from loan principal,
rate, and term.
These defaults are a starting point — please adjust them based on your market, property
condition, and experience. Local taxes, insurance, HOA dues, and rent levels can vary significantly.
Last reviewed by the Dogality Test Team on Sep. 30, 2025.