Rental Property Calculator
Is that duplex a good investment? Enter the price, rent, and costs to see the monthly cash flow, cap rate, and cash-on-cash return — the three numbers investors live by.
How to use this calculator
- Enter purchase price.
- Enter down payment.
- Enter interest rate.
- Enter loan term.
- Enter monthly rent.
- Enter annual property tax.
- Enter annual landlord insurance.
- Enter maintenance & repairs (% of price/year).
- Enter vacancy allowance (% of rent).
- Your results appear instantly below and update as you change the numbers.
How this calculator works
Monthly cash flow is rent minus every cost: the mortgage payment, property tax, insurance, a maintenance reserve (the 1%-of-price rule of thumb), and a vacancy allowance (typically 5–8% of rent). The cap rate divides annual net operating income by the purchase price to compare properties independent of financing; cash-on-cash divides annual cash flow by your down payment to show the return on money actually invested.
Frequently asked questions
What is a good cap rate?
Roughly 4–6% in hot, low-risk markets and 7–10% in secondary markets where prices are lower and management is harder. The cap rate ignores financing and appreciation, so use it to compare properties — and cash-on-cash to see what your specific down payment earns.
Why do beginners underestimate costs?
Because vacancy and maintenance feel hypothetical until they happen. A tenant who moves out costs you 1–2 months of rent; a roof or HVAC failure can cost $10,000+. The 5% vacancy and 1%-of-price maintenance reserves in this calculator are the minimum an experienced landlord budgets — treat any month that beats them as upside, not the plan.
Do I need 20% down on an investment property?
Most lenders require 20–25% down on non-owner-occupied loans, and investment rates run higher than owner-occupied. If you are buying with an FHA loan as an owner-occupant and renting out rooms or the other unit, the down payment is lower but you must live there first — house-hacking is the classic way in.
Disclaimer: Results are estimates for general information only and do not constitute financial, tax, or legal advice. Figures reflect 2026 rules and may change. Always confirm current limits and consult a qualified professional before making decisions. Official figures: IRS.gov · 2026 limits per IRS tax inflation adjustments.