A rental property calculator estimates monthly cash flow and cash-on-cash return after vacancy, expenses and the mortgage. A $300,000 rental with $2,400 rent and 5% vacancy nets about $263 a month in the default example.
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How to use the rental property calculator
- Enter price, down payment, rate and term.
- Enter monthly rent and expenses.
- Enter a vacancy rate.
- Read cash flow and return.
How the rental property calculator works
The rental property calculator estimates the monthly cash flow from a rental home after vacancy, operating costs and the mortgage. You enter the price, down payment, loan rate and term, monthly rent, monthly expenses and a vacancy rate. The tool works out:
- Effective rent = rent × (1 − vacancy %)
- Cash flow = effective rent − expenses − mortgage payment
- Cash-on-cash return = cash flow × 12 ÷ down payment
The mortgage payment uses the standard amortization formula on the price minus the down payment.
Rental property calculator worked example
A $300,000 house is bought with $60,000 down and a 30-year loan at 6.5%, a payment of $1,516.96. It rents for $2,400 a month, with $500 of expenses and 5% vacancy. Effective rent is $2,280, so the rental property calculator shows cash flow of $2,280 − $500 − $1,516.96 = $263.04 a month. That is $3,156 a year on $60,000 down, a cash-on-cash return of 5.26%. With no vacancy, cash flow rises to $383.04.
| Vacancy | Effective rent | Cash flow | Cash-on-cash |
|---|---|---|---|
| 5% | $2,280.00 | $263.04 | 5.26% |
| 0% | $2,400.00 | $383.04 | 7.66% |
| 10% | $2,160.00 | $143.04 | 2.86% |
Choosing a vacancy rate
Even good rentals sit empty between tenants. A 5% rate is about 18 days a year; 8.3% is one month. Use local vacancy data or your own experience, and allow more for student or seasonal rentals. Enter the rate as a percentage from 0 to 100; anything outside that range is rejected. The down payment must also be between 0 and the price, and rent and expenses cannot be negative.
What to include in expenses
Include property tax, landlord insurance, repairs and maintenance, capital reserves, property management (often 8% to 10% of rent), HOA dues, utilities you pay, and costs of finding tenants. A common shortcut, the 50% rule, assumes operating costs take about half the rent before the mortgage; real figures vary widely. IRS Publication 527 describes which rental expenses can be deducted and how depreciation works.
Cash flow is not the whole return
Total return also includes principal paid down each month, any rise in property value and tax effects such as depreciation. These do not appear in monthly cash flow, and the rental property calculator leaves them out. On the other hand, it also leaves out closing costs and repairs at purchase, which add to the cash you put in and lower the true cash-on-cash return.
Stress-test the deal
A deal that works only with full occupancy and no repairs is fragile. Run the numbers with 10% vacancy, higher expenses and a rate one point higher. In the example, 10% vacancy cuts cash flow to $143.04 a month. If cash flow turns negative in a mild stress case, you would be paying to own the property.
The effect of financing
A larger down payment lowers the mortgage and raises cash flow, but may lower cash-on-cash return. Paying all cash makes the cash-on-cash figure blank, since there is no down payment to divide by; use the cap rate calculator for that case.
Screening many listings
When comparing listings, run each one with the same vacancy and expense assumptions so the results are comparable, then look closely only at the best few.
Tips
- Use market rents from similar nearby units.
- Keep a cash reserve for repairs and vacancies.
- Run the rental property calculator for best, likely and worst cases.
- Check local landlord rules and licensing.
Estimates for education only, not financial advice. Your lender’s figures are final.
Related converters and calculators
Related calculators:
- Cap rate calculator: cap rate and NOI
- Mortgage calculator: payments
- ROI calculator: return
- Rent calculator: rent budget
Other ways to size a deal: the cap rate calculator, the BRRRR calculator and the Airbnb income calculator.
Sources
IRS Publication 527: Residential rental property; CFPB: Buying a house.
Formula and method
Loan = price - down. Payment = PMT(loan, rate, years*12). Effective rent = rent * (1 - vacancy/100). Cash flow = effective rent - expenses - payment. Cash-on-cash ROI% = (cash flow * 12 / down) * 100 when down > 0.
Simple leveraged rental cash-flow sketch. Ignores taxes, capex reserves, and appreciation.
Questions about this calculator
What is a good cash flow for a rental?
It varies; many investors want positive cash flow after reserves.
What vacancy rate should I use?
Often 5% to 10%, based on local data.
What is cash-on-cash return?
Yearly cash flow divided by the cash invested.
Does it include appreciation?
No.
Does it include closing costs?
No.
Check the assumptions and units before relying on a result. Financial, tax and health estimates do not replace advice for your individual circumstances.
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