How to Calculate Rental Property Cash Flow After All Taxes

What "Cash Flow" Actually Means for a Rental Property

After-tax cash flow is the dollars remaining in your account after every expense and every tax obligation is satisfied. It is not net operating income (NOI). It is not cap rate. It is the number that answers one question: did this property put money in your pocket or take it out?

The calculation runs in four distinct layers:

1. Gross rental income minus vacancy allowance
2. Minus operating expenses (insurance, taxes, maintenance, management fees, HOA)
3. Minus annual debt service (principal plus interest on the mortgage)
4. Minus income taxes owed on the taxable portion of rental profit

Each layer is non-optional. Investors who stop at layer two or three are running a fantasy number.

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Layer 1 and 2: Pre-Tax Cash Flow

Pre-tax cash flow sets the baseline. Start here before adding any tax calculation.

Formula: Pre-Tax Cash Flow = (Gross Rent x (1 - Vacancy Rate)) - Operating Expenses - Annual Debt Service

Example A. A single-family rental in Atlanta rents for $2,400 per month. Assume a 5% vacancy rate, $7,200 per year in operating expenses (taxes, insurance, maintenance, management), and a 30-year fixed mortgage at 7.1% on a $280,000 loan, producing a monthly payment of $1,882.

• Effective gross income: $2,400 x 12 x 0.95 = $27,360
• Operating expenses: $7,200
• Annual debt service: $1,882 x 12 = $22,584
• Pre-tax cash flow: $27,360 - $7,200 - $22,584 = negative $2,424

This property loses money before taxes even enter the picture. A buyer who skipped this step and focused only on gross rent would have mispriced the deal entirely.

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Layer 3: Calculating Taxable Rental Income

Taxable rental income is not the same as pre-tax cash flow. The IRS taxes profit differently than it taxes cash flow because depreciation is a non-cash deduction.

Formula: Taxable Rental Income = Effective Gross Income - Operating Expenses - Mortgage Interest - Depreciation

Depreciation on residential rental property uses a 27.5-year straight-line schedule applied to the building value only, not the land.

Example B. A duplex in Phoenix generates $38,400 per year in effective gross income. The owner paid $420,000, with $80,000 allocated to land. The depreciable basis is $340,000. Annual depreciation: $340,000 / 27.5 = $12,364. Annual mortgage interest on a $336,000 loan at 6.875%: approximately $22,900 in year one. Operating expenses: $9,600.

• Taxable rental income: $38,400 - $9,600 - $22,900 - $12,364 = negative $6,464

The property shows a tax loss of $6,464 despite generating real cash. That loss may offset other passive income, or, if the owner qualifies as a real estate professional under IRS Section 469, it may offset ordinary income. The $25,000 passive activity loss allowance phases out between $100,000 and $150,000 of modified adjusted gross income (MAGI).

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Layer 4: Applying the Correct Tax Rates

Three separate federal taxes can apply to rental income. Apply each one to the correct base.

Federal ordinary income tax applies to net rental profit at your marginal rate. In 2025, rates run from 10% to 37%. A married couple filing jointly with $250,000 in total income pays 24% on rental profit that falls in that bracket.

Net Investment Income Tax (NIIT) adds 3.8% on top of federal ordinary rates for passive rental income once MAGI exceeds $200,000 (single) or $250,000 (married filing jointly). It applies to net rental profit, not gross rent.

State income tax varies by state. California taxes rental income as ordinary income at rates up to 13.3%. Texas and Florida impose no state income tax. Always apply the marginal state rate to net rental profit.

Example C. The Phoenix duplex from Example B generates $38,400 in effective gross income. Taxable income after deductions is negative, so no federal income tax applies this year. But assume the property is held debt-free in year 10. Mortgage interest is now $18,400. Depreciation continues at $12,364.

• Taxable income: $38,400 - $9,600 - $18,400 - $12,364 = negative $1,964

Still a paper loss. Pre-tax cash flow, however, is positive: $38,400 - $9,600 - (principal + interest of $26,760) = $2,040. The investor pockets $2,040 in cash but owes no income tax this year because depreciation creates a paper loss.

This is the core tax advantage of rental real estate. Depreciation shelters cash flow from current taxation. The catch arrives at sale.

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The Depreciation Recapture Cost You Cannot Ignore

Depreciation recapture taxes all accumulated depreciation at a flat 25% federal rate under IRS Section 1250. This is not a capital gains rate. It is a fixed 25% regardless of your bracket.

On the Phoenix duplex held for 15 years: $12,364 x 15 = $185,460 in total depreciation claimed. At a 25% recapture rate, the federal tax owed at sale on that accumulated depreciation is $46,365, before any state tax.

Include this liability in your long-term return model. Investors who calculate only annual cash flow and ignore recapture routinely overstate their total return by 8 to 12 percentage points on a 10-year hold.

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The Complete After-Tax Cash Flow Formula

After-tax cash flow combines all four layers into one number.

Formula: After-Tax Cash Flow = Effective Gross Income - Operating Expenses - Annual Debt Service - Federal Income Tax on Rental Profit - NIIT (if applicable) - State Income Tax on Rental Profit

If taxable rental income is negative due to depreciation and interest deductions, and the passive loss rules permit you to use that loss, your after-tax cash flow will exceed your pre-tax cash flow. That is the correct scenario for a well-structured rental acquisition in years one through five.

If taxable rental income is positive because the property is mostly or fully paid off, apply your marginal federal rate, the 3.8% NIIT if your MAGI exceeds the threshold, and your state rate. Sum those three tax amounts and subtract them from pre-tax cash flow.

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Run Your Property's Numbers Before You Commit

The difference between a 6.2% after-tax cash-on-cash return and a 4.1% return is not a rounding error. On a $120,000 down payment, it is the difference between $7,440 and $4,920 per year, a gap of $2,520 annually and $25,200 over a decade before compounding.

The CalcMoney mortgage calculator lets you input your loan amount, rate, and term to isolate your exact debt service figure, the starting point for every layer of this analysis. Model multiple rate scenarios before you lock in. A 0.5% rate difference on a $300,000 mortgage is $900 per year in debt service and shifts your after-tax cash flow by a material amount.

Use the calculator above to set your debt service baseline. Then apply the four layers in order. The number you end up with is the only cash flow figure worth making a decision on.

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Results are estimates for informational purposes only. Consult a licensed financial professional before making financial decisions.