Rental Property Cash Flow Calculator: Monthly & Annual Analysis

Why Cash Flow Is King

Cash flow is the lifeblood of buy-and-hold real estate investing. Positive cash flow means the property pays you every month. Negative cash flow means you subsidize the property — hoping appreciation or future rent growth will justify the investment.

Accurate cash flow analysis separates sustainable portfolios from ones that crumble when markets shift or vacancies spike.

Building a Cash Flow Statement

Start with gross rental income, subtract vacancy allowance, then subtract all operating expenses and debt service. What remains is your net cash flow.

• Gross rent (all units combined)
• Vacancy loss (typically 5–10%)
• Property taxes and insurance
• Maintenance and capital reserves
• Property management fees
• Mortgage principal and interest
• HOA, utilities, and other owner-paid costs

Cash Flow vs. NOI

Net Operating Income (NOI) excludes mortgage payments — it is a property-level metric. Cash flow subtracts debt service to show what hits your bank account. Both matter: NOI for property comparison, cash flow for personal finance planning.

Use the Cash Flow Calculator

Model your complete income and expense picture. The calculator shows NOI, monthly and annual cash flow, a full waterfall breakdown, estimated cash on cash return, and an assessment of whether the deal meets common investment thresholds.

Adjust assumptions to stress-test: what if vacancy doubles? What if you self-manage and eliminate the management fee? Sensitivity analysis builds confidence in your numbers.