About the Rental Property Calculator
This rental property calculator gives you a full first-pass analysis of an investment property in one screen. Enter the price, down payment, closing costs, mortgage rate, rent, vacancy and monthly operating expenses, and it returns the mortgage payment, monthly and yearly cash flow, net operating income, cap rate and cash-on-cash return.
It then projects the next ten years: the property value grows at your appreciation rate, the loan balance falls with every payment, and the chart tracks your equity alongside the cash flow you have collected. The table breaks down each year so you can see how much of your wealth comes from cash flow, loan paydown and appreciation.
Use it to screen listings, compare two properties, or stress-test a deal at a higher rate or vacancy. To keep the projection transparent, rent and expenses are held flat in today’s dollars and selling costs are not deducted; treat the equity figure as paper equity, not cash in hand.
With the default inputs, the monthly cash flow is $93.07. Change any value above to recalculate instantly.
How to use the rental property calculator
- 1Enter the purchase price, down payment and closing costs.
- 2Enter the mortgage rate and loan term.
- 3Add the expected monthly rent and a realistic vacancy rate.
- 4Add monthly operating expenses — tax, insurance, maintenance, management and HOA.
- 5Set an appreciation rate and review cash flow, returns and the 10-year equity chart.
Formula and method
The mortgage payment uses the standard amortization formula on the loan amount (price × (1 − down payment %)). Monthly cash flow is rent after the vacancy allowance, minus operating expenses and the mortgage. Net operating income is the same figure before the mortgage, and the cap rate divides it by the purchase price.
For the projection, property value compounds at the appreciation rate each year and the loan balance is calculated from the amortization schedule. Equity is value minus balance. The 10-year paper profit is the growth in equity above your down payment plus the cash flow collected, minus the closing costs you paid; it ignores selling costs, taxes and rent growth.
- NOI
- Net operating income = (effective rent − expenses) × 12
- P&I
- Monthly principal and interest payment
- g
- Annual appreciation rate
- Equity(y)
- Price × (1 + g)^y − loan balance after y years
Worked examples
$300k single-family rental, 25% down at 7%
A $225,000 loan at 7% costs $1,496.93 a month. Rent of $2,200 less 5% vacancy is $2,090; after $500 of expenses the property clears about $93 a month. The cash-on-cash return is only 1.3%, but at 3% appreciation and with loan paydown, equity grows to about $210,000 in ten years.
Cash-flow market: $180k house renting for $1,800
Borrowing $144,000 at 7% costs $958.04 a month. Rent after 8% vacancy is $1,656; subtracting $550 of expenses and the mortgage leaves about $148 a month. The rent is exactly 1% of the price, so the deal passes the 1% screening rule.
15-year loan on a $400k property
A $280,000 loan over 15 years at 6.25% costs $2,400.78 a month, which pushes cash flow to about −$161 a month even though NOI is a healthy $26,880. The shorter term pays the loan down much faster, trading monthly cash for equity.
Frequently asked questions
What is a good cash flow for a rental property?+
Many investors aim for at least $100–$200 per door per month after all expenses and reserves, or a cash-on-cash return of 8% or more. Lower cash flow can still work if you expect strong appreciation, but it leaves less cushion for repairs and vacancies.
What is the 1% rule?+
The 1% rule says monthly rent should be at least 1% of the purchase price — $3,000 a month for a $300,000 property. It is a quick screening test, not an analysis; many good deals in expensive markets fail it, and some that pass have high expenses.
How much should I budget for rental expenses?+
The 50% rule estimates that operating expenses — excluding the mortgage — take about half of rent over time. A line-by-line budget usually includes property tax, insurance, 5%–10% for maintenance, 5%–10% for capital reserves and 8%–10% for management.
Does this calculator include appreciation in cash flow?+
No. Cash flow only counts rent in and expenses out. Appreciation and principal paydown show up in the equity projection and the 10-year paper profit, because you cannot spend them until you sell or refinance.
What vacancy rate should I use?+
A 5%–8% allowance, roughly two to four weeks a year, is typical for stable long-term rentals. Use a higher rate for student housing, seasonal areas or properties that need work between tenants.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.