Run your own numbers

Four numbers to start: the price, your down payment, the interest rate and the rent the other units bring in. Every other field has a default you can change.

new to house hacking? →see the city pages →

This free house hacking calculator shows what a small multifamily home would cost you each month after your tenant’s rent is applied. Your effective housing cost. Enter the price, down payment, interest rate, and the rent the other unit should bring in; you get your monthly out-of-pocket cost, cash flow, and cash-on-cash return. No account, no paywall. For example, when I updated this page in October 2026, a $500,000 duplex with $2,400 in tenant rent, $180 of owner utilities and a 10% reserve on both units’ rent worked out to about $2,155 a month out of pocket. The calculator below loads this week’s rate, so its number will differ.

Updated October 2026.

House Hacking Calculator

Free forever · No signup

Run the actual numbers on a duplex, triplex, or fourplex, with you living in one unit

Property & Financing

Enter the purchase price, down payment percentage, interest rate, loan term, annual property tax and insurance, and any monthly mortgage insurance to build the full payment.

$
%
%
$
$
$

Rental Income

Enter conservative monthly rent for the units you will not live in, and the market rent your own unit would fetch after you move out.

$
Type the rent the tenant pays you. HUD’s rent figures include utilities, so take about $180 off them first.
$

Operating Assumptions

The reserve is this calculator’s convention: 10% of every unit’s rent, yours included, for empty months, repairs and replacements, counted in the live-in figure and the fully rented view; management counts only after you move out. The metro pages on this site use the same 10%.

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Your own unit’s utilities plus any building bills (water, trash, common areas). $180 is the US median gap between gross and contract rent (Census ACS 2024); a renter’s rent usually covers these, so the comparison with your rent needs them.
% of rent
10% of every unit’s rent, yours included, for empty months, repairs and replacements together. The same convention as Deal Math and the metro pages.
%
% of price

Results

Results show your monthly payment breakdown, your effective housing cost while you live there, and cash flow, cap rate and cash-on-cash return when fully rented.

Monthly Payment Breakdown

Principal & Interest $0
Taxes, Insurance & PMI $0
Total Monthly Housing Cost (PITI) $0

While You Live There

Rental Income from Other Units $0
Utilities you pay $0
Reserve (all units) $0
Your Estimated Effective Housing Cost $0

While you live here: rent in, mortgage out

Tenant rentYour sharePrincipal & interestTaxes, insurance & PMIUtilities & reserve

When Fully Rented (After You Move Out)

Gross Monthly Rent $0
Less: Reserve & Management (your own utilities stop when you move out; building bills are yours to add) $0
Net Operating Income (monthly) $0
Monthly Cash Flow (after debt service) $0
Cash-on-Cash Return 0%
Cap Rate 0%
Total Cash Invested (DP + Closing) $0
Estimates only. Verify with your lender, CPA, and inspection before purchase.

Not sure what to enter in each field, or where the numbers should come from: I wrote a step-by-step guide to using this calculator, including a worked example with real listing numbers.

Embed this tool on your site (free)

All eleven widgets, plus the terms of use, are listed on the calculator embed page.[S1]

Put this calculator on your site, free

Run a real-estate or personal-finance site? Embed this house-hacking calculator on any page at no cost. Copy the code below and paste it into an HTML/embed block. It stays up to date automatically and includes a small credit link back here.

<iframe id="vtv-hh-calc" src="https://vantovault.com/tools/calculator/widget/" title="VanToVault House Hacking Calculator" width="100%" height="3282" scrolling="no" loading="lazy" style="width:100%;max-width:900px;border:1px solid #e5e5e5;border-radius:10px"></iframe>
<script>window.addEventListener("message",function(e){var f=document.getElementById("vtv-hh-calc");if(f&&e.source===f.contentWindow&&e.data&&e.data.vtvCalcHeight){f.style.height=e.data.vtvCalcHeight+"px"}});</script>
<p>Powered by <a href="https://vantovault.com/tools/calculator/">VanToVault House Hacking Calculator</a></p>

Frequently asked questions

What does the house hacking calculator do?

The house hacking calculator is a free tool that estimates your effective housing cost. You enter a property price, your down payment, and local rents, and it shows that figure (the monthly payment, the utilities you pay as the owner and a 10% reserve on every unit’s rent, minus the rent the other unit brings in), plus cash flow and returns once fully rented. Compare that cost with your rent today. The 10% reserve covers empty months, repairs and replacements, and it counts in both the live-in number and the fully rented view.

Is the calculator really free?

Yes. The house hacking calculator is free to use with no signup and no email required. VanToVault also has a down-payment budget tool and a rent-vs-buy comparison, all free.

What is effective housing cost?

Effective housing cost is your total monthly payment (principal, interest, taxes, insurance and FHA mortgage insurance), plus the utilities you pay as the owner and a 10% reserve on every unit’s rent, minus the rent you collect from the other unit. It is the number an owner-occupant actually pays to live, and the right number to compare against rent.

// More free VanToVault tools

VanToVault launched on FazierVanToVault House Hacking Calculator approved on SaaSHub
Van to Vault House Hacking Calculator - See if a duplex could cost less than your rent | Product Hunt
Next step

You have a monthly number. Now find where it works.

Try the duplex markets index. I screen every two-to-four-unit listing across 83 metro areas and rank the metros where the math holds up, most of them with owning ahead of renting.

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Sources

  1. [S1] Van to Vault, read 24 September 2026: “Van to Vault publishes eleven of them, free to use on any site, with no limit on how many people run them.” vantovault.com.

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