Rental Property Calculator

This rental property calculator is the one I run before I let myself get excited about a listing. You fill in the purchase side (price, closing costs, rehab), the financing (down payment percent, rate, term), the income (rent, other income, vacancy) and the full expense stack. Out come monthly cash flow, annual net operating income, cap rate, cash on cash return, total cash needed, and a year by year projection of loan balance, equity, cumulative cash flow and total return including principal paydown and appreciation. It runs entirely in your browser, so nothing you type is uploaded or stored.

I built this because I kept rebuilding the same spreadsheet on my phone outside open houses, and because most free calculators leave out the expense lines that actually kill deals. If you only want fast triage, the rental deal screener runs the classic rules of thumb in half a minute. This is for what comes after, when a property has earned a real look. Everything here is arithmetic on your assumptions, not tax or financial advice.

How to use

1. Fill in the purchase block first: contract price, estimated closing costs, and any rehab you plan to finish before the first tenant.
2. Set the financing: down payment percentage, interest rate and term. The loan amount and monthly payment come from those three.
3. Enter income: expected monthly rent, other income such as parking or pet fees, and a vacancy percentage you would defend to a lender.
4. Work down the expenses: property tax, insurance, HOA, maintenance percent, capex reserve percent, management percent, owner paid utilities and other.
5. Read the headline results: monthly cash flow, annual net operating income, cap rate, cash on cash return and total cash needed.
6. Set growth assumptions for rent, expenses and appreciation, then read the year by year table for loan balance, equity and cumulative return.
7. Change one input at a time and watch which output moves most. That sensitivity check is the real value of the exercise.

Why use our rental property calculator?

Maintenance and capex are percentages of rent here rather than optional extras, and that is the opinionated part of the tool. The number I got wrong first was capex. My first duplex penciled at a little over two hundred dollars a month, then a water heater, a roof section and a furnace arrived inside three years and ate all of it. Roofs and HVAC do not bill you monthly, but they bill you.

Separating net operating income from cash flow is deliberate. NOI leaves the mortgage out, so it describes the building. Cash flow puts the mortgage back in, so it describes your month. The cap rate shown is NOI over the all in purchase price rather than the sticker price, because closing costs and rehab are real money you spent to own the income.

Total cash needed is the figure people underestimate most. The down payment is the obvious piece, but closing costs and rehab push the real number well past it, and cash on cash return means nothing until that denominator is right. If you want that one metric on its own, the cash on cash return calculator isolates it.

The projection table shows the working instead of handing you a single confident number. Rent growth, expense growth and appreciation are assumptions you choose, not forecasts I am making, and I default them conservatively on purpose. Run the table once with appreciation set to zero and see whether you still like the property. If it only works because of appreciation, you are buying a lottery ticket with a mortgage attached.

There is no signup, no export paywall and no email capture. What I refuse to add is a lead form that hands your deal numbers to a lender before you have decided anything. The math happens locally and closing the tab is a complete delete.

Who is this tool for?

Screening a listing you found this morning is the everyday use. Price and taxes come from the listing, rent comes from comparable units nearby, and ten minutes later you know whether to book a showing or move on. Doing this on twenty properties teaches you more about your market than any course.

Testing financing structures is where the tool earns its keep. Run the same property at fifteen percent down and again at twenty five percent down, and watch cash flow and cash on cash return pull in opposite directions. More money down buys a calmer month and a weaker return on capital, and seeing both move at once is how you decide which one you are optimizing for.

Preparing for a lender conversation is a quieter use. Investor loans are often sized on debt service coverage rather than your paycheck, so once the NOI looks solid, drop it into the DSCR calculator to see the ratio an underwriter cares about.

Reviewing something you already own works too. Enter today's market value instead of your old purchase price, use your real rent and expenses from the last twelve months, and see what return the property generates on the equity sitting inside it. Sometimes the honest answer is to recycle that capital, which is why the BRRRR calculator sits next door.

Frequently asked questions