Free owner tool

Rental Cash Flow Calculator

Estimate monthly and annual rental cash flow after vacancy, operating expenses and mortgage debt service.

Free browser-based tool · Updated August 3, 2026

Monthly cash flow

How to use this tool

Rental Cash Flow Calculator guide

Cash flow shows what remains after vacancy, recurring operating costs and debt service. Use conservative assumptions and compare the result with actual property records before relying on the estimate.

Cash flow versus NOI

NOI measures the property before financing. Cash flow subtracts debt service and therefore changes with loan amount, interest rate and amortization. Two owners can have the same property NOI but different cash flow because their financing differs.

Build a realistic expense estimate

Include taxes, insurance, management, repairs, recurring utilities, HOA charges, landscaping and a reserve for future replacements. A property can appear profitable when large but predictable costs are omitted.

Stress-test the property

Run the calculator again with lower rent, higher vacancy, higher insurance and a repair allowance. A deal that works only under perfect assumptions may have little margin for error.

Questions and answers

Frequently asked questions

What is positive rental cash flow?

Positive cash flow means effective rental income exceeds operating expenses and debt service for the period analyzed.

Should principal payments be included?

The full required mortgage payment is normally included when estimating spendable cash flow, even though principal reduction also builds equity.

Is cash flow the same as profit?

Not exactly. Tax treatment, depreciation, capital expenditures and sale proceeds are not fully represented in a simple cash-flow estimate.

Need a property-specific management analysis?

Online calculators provide planning estimates. Pro Plus Realtors can review the property, leasing conditions, Section 8 requirements and operating records in more detail.

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