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House Hack Cash Flow Calculator

House hacking — living in one unit, renting others — can turn your housing cost into cash flow. Whether a duplex, triplex, or single-family with ADU, this calculator sizes effective housing cost and return on the minimal down payment required for owner-occupied financing.

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Your effective housing cost

$2,649

Total rental income

$1,400

Total monthly property cost

$3,937

Monthly P&I

$2,852

Annual cash flow (positive = profit)

-$31,790

Cash-on-cash ROI

-100.1%

Total cash invested

$31,750

How the math works

$475K duplex, 5% down FHA: $23,750 down + $8K closing = $31,750 in. Mortgage $2,850 + tax $475 + ins $140 + maint $200 + MIP $270 = $3,935/mo. Rental unit at $1,400 × 92% = $1,288. Effective housing cost: $2,647/mo. Cheaper than renting a comparable unit at $2,400-$3,000.

If rent fully covers the payment, effective cost goes negative (positive cash flow). A 3-unit triplex with two rentals at $1,200-$1,500 each often hits net cash flow positive. Best wealth-building move for early-career professionals who qualify for owner-occupied financing.

Editorial noteMaintained by EveryCalc - Reviewed June 2026

EveryCalc calculators are designed for fast, practical estimates with transparent inputs and no required account. We use plain formulas, visible assumptions, and related tools so visitors can check the result from more than one angle.

Results are informational only. For financial, tax, legal, medical, construction, or other high-impact decisions, verify the output against primary sources or a qualified professional.

Learn more about our review process on the EveryCalc methodology page.

How this calculator works

What this page estimates

This House Hack Cash Flow Calculator is built to give a quick, browser-based estimate for house hack cash flow. House hacking — living in one unit, renting others — can turn your housing cost into cash flow. Whether a duplex, triplex, or single-family with ADU, this calculator sizes effective housing cost and return on the minimal down payment required for owner-occupied financing. The inputs stay on the page during normal use, and the result should be treated as an estimate for planning, comparison, or education rather than professional advice.

Calculation approach

The calculator applies the standard relationship implied by the inputs, then formats the answer so it can be checked and reused. For finance tools, the most important step is using consistent units, rates, time periods, and assumptions before comparing the result with another calculator or outside quote.

Example workflow

For example, start with a realistic value you already know, change one input at a time, and watch how the answer moves. That makes it easier to tell whether the result is being driven by the main amount, the rate, the time period, or a unit conversion.

Practical checks

  • Use current, real-world numbers when the result affects money, health, tax, or legal decisions.
  • Run a low, base, and high case when the inputs are estimates.
  • Check the related calculators below when the next decision depends on a different assumption.

How to interpret the house hack cash flow result

Best use

Use the result as a planning number for comparing payments, rates, returns, tax reserves, or cash-flow choices before you request a quote or make a commitment.

Cross-check

Compare the answer with the contract, lender estimate, tax form, brokerage statement, payroll record, or invoice that will control the real-world outcome.

Watch for

Do not rely on a single optimistic rate, return, or fee assumption. Money pages work best when you run low, base, and high cases and keep professional advice separate from the estimate.

This page belongs to the Finance calculator library, so the answer should be read in the context of the decision you are modeling rather than as a universal rule.

Before relying on this house hack cash flow estimate

Most calculator mistakes come from the inputs, not the arithmetic. Use this short audit before you reuse the answer in a spreadsheet, quote, application, or important conversation.

Confirm source numbers

Match balances, rates, fees, taxes, income, and payment dates against the lender quote, payroll record, tax form, statement, invoice, or contract.

Separate cash flow from total cost

A lower monthly payment can still cost more over time if fees, interest, taxes, or a longer term are hidden in the structure.

Run conservative cases

Test at least one higher-cost or lower-return case before using the output for a purchase, refinance, investment, loan, or tax decision.

Rerun this page when the rate, price, term, fee, tax rule, income, expense, or expected holding period changes.

How to Use

  1. Enter purchase price, owner-occupied down payment %, and mortgage details.
  2. Enter monthly rental income from each non-owner unit.
  3. Add operating cost including your unit's maintenance share.
  4. See effective housing cost (what YOU pay per month), net cash flow, and cash-on-cash ROI.

Frequently Asked Questions

Can I use FHA for a house hack?

Yes. FHA allows 2-4 unit owner-occupied with 3.5% down. 5+ unit requires commercial financing. You must live in one unit for at least 12 months to maintain FHA eligibility.

What about conventional owner-occupied?

Fannie/Freddie allow 2-4 unit owner-occupied with 5-15% down. Slightly higher down than FHA but no MIP (FHA has permanent MIP at low down payment). Strong credit (700+) makes conventional cheaper long-term.

Does rental income count for qualification?

Yes but with a haircut. Lenders count 75% of projected rental income from non-owner units for DTI. Requires signed leases or market rent appraisal. Subject property income counts after 2-3 years of tax returns; at purchase, it's based on appraisal.

Is it worth it?

Usually yes for 2-4 unit deals where rental income covers 60-100% of mortgage + operating. Your effective housing cost drops to $200-$800/mo vs $1,800-$2,500 in rent. Build equity in the same time period. Real wealth-builder for 20s-30s.

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