These are the questions people ask most often about rental property cash flow, and about how this calculator specifically arrives at its numbers. If you're new to rental investing, start with "What's a good cash flow target?" and "What's the difference between cash flow and profit?" below — the rest build on those two ideas.
What's a good cash flow target? +
There's no single number that's "correct" everywhere, because it depends on your market, your financing, and your goals. Some investors use a personal screen such as a certain number of dollars per unit per month before a deal feels worth the risk and effort; these figures are anecdotal, not an industry standard, and vary widely. Others in lower cost-of-living or lower cash flow markets accept smaller monthly numbers because they're underwriting for appreciation or equity growth instead. Rather than chasing a specific dollar figure you saw online, it's usually more useful to decide what monthly cushion would let you sleep at night if a major repair or a vacancy hit that specific property, and use that as your personal minimum.
Why include vacancy and maintenance reserves if nothing's broken right now? +
Because those costs are likely over a long ownership period even though they rarely land in a predictable month. A furnace that lasts 15 years still needs to be replaced eventually, and a unit that's occupied today will eventually turn over between tenants. Reserving a percentage of rent every month for these costs, whether you spend it that month or not, means the money is already set aside when the bill actually arrives instead of coming as a surprise that eats into (or wipes out) that month's cash flow.
What's the difference between cash flow and profit? +
Cash flow, as this calculator defines it, is the cash left over each month after operating expenses and the mortgage payment. Profit (or return) is a broader concept that also includes non-cash benefits like the equity you build as your mortgage principal is paid down, any appreciation in the property's value, and tax benefits like depreciation. A property can have modest or even negative monthly cash flow while still building meaningful long-term wealth through those other channels — and the reverse is also true, so cash flow alone shouldn't be your only measure of whether a property is a good investment.
Should I use gross rent or net rent in the calculator? +
Use your expected gross rental income — the full rent a tenant would pay before any deductions. The calculator itself handles subtracting management, maintenance, vacancy, and other costs from that gross figure. If you enter a rent number that's already been reduced for expenses, the calculator will double-count those deductions and understate your true cash flow.
Why does the mortgage field ask for PITI instead of just principal and interest? +
Principal and interest is only part of a typical monthly housing payment. Property taxes and insurance are real, recurring costs that most lenders collect monthly through an escrow account, and leaving them out is one of the most common ways beginners overstate a property's cash flow. Entering your full PITI payment keeps the estimate honest.
Does this calculator account for property appreciation or equity growth? +
No. This tool is scoped specifically to monthly operating cash flow — income minus expenses and the mortgage payment. It doesn't project future property value, calculate how much of each mortgage payment goes toward principal versus interest, or estimate tax benefits like depreciation. Those are legitimate and important parts of a property's total return, but they require additional assumptions beyond what a fast, anonymous cash flow estimate should ask for.
What percentage should I use for property management if I plan to self-manage? +
You can set it to zero if you're certain you'll always self-manage and want to see the cash-flow impact of doing so. But many experienced landlords budget a management percentage even when self-managing, because it accounts for the real value of their own time and creates a more realistic comparison if they ever decide to hire a manager later.
Is my data stored anywhere? +
No. Every calculation happens locally in your browser using JavaScript. None of the numbers you enter — rent, mortgage payment, or any other field — are sent to or stored on our servers, and nothing is saved once you close or refresh the page.
Can I use this calculator for a multi-unit property? +
Yes, as long as you combine the total expected rent across all units into the "monthly rental income" field and use expense figures (mortgage, insurance, taxes) for the property as a whole rather than per unit. The output will be your estimated cash flow for the entire property, not per individual unit — divide by the number of units yourself if you want a per-unit figure.
Is this financial or investment advice? +
No. This calculator and the content on this site are educational tools meant to help you understand and estimate rental cash flow. They are not financial, investment, tax, or legal advice, and the results are estimates based only on the numbers you enter. Verify your actual mortgage terms, tax assessments, and insurance costs with your lender, local tax authority, and insurance provider, and consult a qualified professional before making a real estate investment decision.