Rental Property Calculator & Cash Flow Estimator
Enter a purchase price, rent, and expenses to instantly see monthly cash flow, cap rate, and cash-on-cash return — plus whether the deal clears the 1% and 50% rules.
Property
We pull beds/baths/sqft, value and a rent estimate from county records + comps (11 DFW counties). Outside those? .
How the rental property calculator works
This free rental calculator turns a few inputs — purchase price, expected monthly rent, operating expenses, and your loan terms — into the numbers landlords actually underwrite on: monthly cash flow, net operating income (NOI), capitalization rate, and cash-on-cash return. Change any field and every result updates instantly, so you can screen a listing in seconds before you ever call an agent.
Monthly cash flow is the money left after the mortgage and expenses: Cash Flow = Rent − Operating Expenses − Mortgage Payment. Operating expenses typically include property taxes, insurance, property management (8–10% of rent), repairs and maintenance, vacancy allowance, and any HOA dues — but not the loan payment, which is counted separately.
Key formulas & rules of thumb
Cap rate measures return independent of financing: Cap Rate = Annual NOI ÷ Purchase Price. In most Dallas–Fort Worth submarkets a 5–7% cap rate is typical for single-family rentals; higher is better for cash flow, lower usually means appreciation-driven markets.
Cash-on-cash return measures return on the actual cash you invest: Cash-on-Cash = Annual Pre-Tax Cash Flow ÷ Total Cash Invested (down payment + closing costs + rehab). The 1% rule is a fast filter — monthly rent should be at least 1% of the purchase price. The 50% rule assumes operating expenses (excluding the mortgage) run about half of gross rent over time, a conservative sanity-check when you don't have exact expense figures yet.
Frequently asked questions
What is a good cap rate for a rental property?
For single-family rentals in DFW, 5–7% is common. Cash-flow investors often target 7%+, while lower cap rates usually reflect stronger appreciation markets. Compare the cap rate to what similar rentals in the same ZIP are trading at rather than a fixed number.
How do I estimate rental expenses?
Include property taxes, insurance, property management (8–10% of rent), maintenance, a vacancy allowance (5–8%), and HOA dues. If you don't have exact figures, the 50% rule — assuming expenses run ~50% of gross rent excluding the mortgage — is a safe starting estimate.
What is the 1% rule?
The 1% rule says monthly rent should be at least 1% of the purchase price (e.g., $2,000/mo on a $200,000 home). It's a quick screen, not a guarantee of cash flow — always run the full numbers, including your loan terms.
What's the difference between cap rate and cash-on-cash return?
Cap rate ignores financing (NOI ÷ price) and measures the property's return; cash-on-cash includes your loan and measures return on the cash you actually put in. A leveraged deal can have a modest cap rate but a strong cash-on-cash return.
Is this rental calculator free?
Yes — it's completely free and requires no signup. Enter your numbers and see cash flow, cap rate, and cash-on-cash instantly. Create a free account only if you want to save deals or pull owner data on off-market rentals.