Rental Property Calculator

What actually decides whether a rental works

Two properties at the same price and rent can be a good deal and a bad one. The difference is never in the headline numbers — it is in the four things below, which is why this calculator asks for them and most do not.

• The expenses nobody charges monthly. Vacancy, maintenance and capital expenditure arrive as a void, a boiler and a roof — years apart, and large. Charged at 5% of rent each they look trivial; left out entirely they turn a $250/month winner into a break-even property that owes you a roof.
• The loan, not the price. A point of interest on a $150,000 mortgage is about $100 a month — often the whole cash flow. Change the rate on this page before you change anything else and watch what happens.
• Taxes, which vary more than anything else. The default here is 1.1% of price a year, a national middle. Real bills run from under 0.4% to over 2.2% depending on the state, and that spread is bigger than most people's entire margin. Look the real number up.
• Whether a lender will finance it. DSCR below about 1.20 makes an investment loan hard to get regardless of how the deal reads, so a property can be profitable on paper and unfinanceable in practice.

Cash flow, cash-on-cash and cap rate are not the same question

They get used interchangeably and they answer different things. Cash flow is dollars per month — it tells you whether the property pays you or bills you. Cash-on-cash divides the annual version by the cash you actually put in, which is how you compare a rental against an index fund or against your next deal. Cap rate ignores your loan entirely, which makes it the only one of the three that compares two properties rather than two financings.

A deal can look strong on one and weak on another, and that is information rather than a contradiction: a large deposit flatters cash flow and drags cash-on-cash down, because the money sitting in the property has to earn its keep too.

Questions people ask

What is a good cash-on-cash return?

8% or better is a common target for a leveraged rental. Below about 5% you are taking landlord risk — tenants, repairs, vacancy — for something close to a passive return. Above 12%, check your expenses before you celebrate; that is more often a missing cost than a great buy.

Should I include management if I manage it myself?

Yes. Self-managing is a job you are choosing to do, and if you ever stop, the deal has to survive paying someone else. A property that only works because you work for free is not really a return.

Why is my cash flow positive but the score low?

Because cash flow is one of five things the score weighs. A property can clear $80 a month and still be a weak deal if that is a 1.5% return on the cash you sank in, or if the rent barely covers the loan. The breakdown under the gauge shows which part is dragging.

Does this need an account?

No, and it never will. The calculation runs in your browser; nothing you type leaves this page. An account gets you saved deals, real rent comparables, stress tests and shareable reports — not access to the maths.