Investment Property Cash Flow Calculator
Estimates annual cash flow from a rental property by subtracting your mortgage payment and operating expenses from rental income. Use it when evaluating whether a rental property will generate positive returns.
Last updated: May 2026
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About this calculator
Annual cash flow is the money left over after collecting rent and paying all property-related costs. The mortgage payment is calculated using the standard amortization formula: M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where P is the loan amount (property price × (1 − down payment %)), r is the monthly interest rate (annual rate ÷ 12), and n is the total number of payments (loan term in years × 12). Operating expenses such as insurance, property taxes, maintenance, and management fees are subtracted monthly. Annual Cash Flow = (Monthly Rent − Monthly Mortgage Payment − Monthly Operating Expenses) × 12. A positive result means the property generates income above all costs, while a negative result signals that the rent does not cover expenses — a critical signal before committing capital.
How to use
Suppose you buy a $300,000 property with 20% down ($60,000), a 7% interest rate, 30-year term, rent of $2,200/month, and $500/month in expenses. Loan amount = $240,000. Monthly rate = 7%/12 = 0.5833%. n = 360 payments. Monthly mortgage ≈ $240,000 × (0.005833 × 1.005833³⁶⁰) / (1.005833³⁶⁰ − 1) ≈ $1,597. Annual cash flow = ($2,200 − $1,597 − $500) × 12 = $103 × 12 = $1,236/year. This property generates modest positive cash flow.
Frequently asked questions
What is a good annual cash flow for a rental property investment?
Most experienced investors target at least $100–$200 per month ($1,200–$2,400/year) per unit as a baseline for positive cash flow. However, the ideal amount depends on the market, property price, and your financing terms. Higher-priced markets may yield lower cash flow but stronger appreciation, while cash-flow-focused markets offer the opposite. Always factor in vacancy allowances (typically 5–10% of rent) and capital reserve contributions before declaring a property profitable.
How does the down payment percentage affect rental property cash flow?
A larger down payment reduces your loan principal, which directly lowers the monthly mortgage payment and improves cash flow. For example, increasing a down payment from 20% to 30% on a $300,000 property reduces the loan by $30,000, cutting monthly payments by roughly $200 at a 7% rate. However, a larger down payment also ties up more capital, reducing the funds available for additional investments. Investors must balance improved cash flow against reduced leverage and opportunity cost.
Why should I include operating expenses when calculating rental property cash flow?
Operating expenses — including property taxes, insurance, maintenance, vacancy allowances, and property management fees — can easily consume 35–50% of gross rental income. Ignoring them produces an inflated, unrealistic picture of profitability. A rule of thumb called the 50% rule estimates that half of gross rents will go toward operating expenses (excluding the mortgage). Properly accounting for these costs ensures you are evaluating true net cash flow rather than a best-case scenario that rarely holds in practice.