House Hacking Calculator

House Hacking: Turning Your Housing Bill Into an Asset

House hacking means buying a two- to four-unit property, living in one unit for at least a year, and letting rent from the other units cover part or all of your housing cost. Owner-occupants can buy with as little as 3.5% down on FHA or 5% on conventional loans. Plan the exit from day one, because when you move out and later sell, the tax rules for your unit and the rental units are different.

It is the most common on-ramp into rental property investing because owner-occupants get financing terms that pure investors cannot. This calculator answers the core question of any house hack: after collecting rent from the units you do not occupy, what does your own housing actually cost each month, and how does that compare to renting a similar place?

The key output is your net housing cost: mortgage plus taxes, insurance, HOA, utilities, and maintenance, minus rental income. Even when that number does not reach zero, the spread between it and market rent is money you can redirect into savings or the next property, all while tenants help pay down your loan.

Financing Options for Owner-Occupants

FHA (3.5% down)

• Down payment: HUD Handbook 4000.1 requires a Minimum Required Investment of at least 3.5% of the adjusted value. Borrowers with credit scores from 500 to 579 are limited to 90% loan-to-value (10% down).
• Property: one to four units, one of which you will occupy. FHA loan limits are set by county and rise with the number of units.
• Mortgage insurance: FHA charges an upfront premium (usually financed) plus an annual premium paid monthly. Get the current figures from your lender; they materially change the payment.
• Rental income: with no rental history, the lender may count 75% of the lesser of the appraiser's fair market rent or the lease rent for the other units as income.
• Three and four units: the property must pass the self-sufficiency test (net rent of all units at 75% of market, or less if the appraiser's vacancy and maintenance estimate is larger, must cover the full PITI payment), and the lender must verify three months of PITI in reserves. The multi-unit property calculator page works through that test with numbers.
• No short-term rentals: on a 2-4 unit FHA loan you sign form HUD-92561 agreeing not to rent units for less than 30 days.

Conventional owner-occupant loans

Freddie Mac's published maximum loan-to-value for conforming purchase loans on two-unit and three- or four-unit primary residences is 95%, which means a down payment as low as 5% for borrowers and loans that meet its other credit, reserve, and mortgage insurance requirements. Conventional private mortgage insurance can usually be removed once you build enough equity, which is one reason some buyers choose it over FHA. Individual lenders may require more down, so compare written loan estimates.

Other routes

Eligible veterans and service members may be able to use a VA loan on an owner-occupied property of up to four units, and some state housing finance agencies offer down payment assistance that can be paired with FHA or conventional loans. Program rules vary, so confirm eligibility with the agency or lender. The financing calculator helps compare payments across down payment levels.

Occupancy Requirements: What “Living There” Means

The low down payment exists because you are buying a home, not an investment, and the loan documents make you promise that.

• FHA: HUD Handbook 4000.1 requires at least one borrower to occupy the property within 60 days of signing the security instrument and intend to continue occupancy for at least one year. FHA defines a principal residence as where you live for the majority of the calendar year, and you can have only one at a time.
• Conventional: the occupancy clause in the Fannie Mae/Freddie Mac uniform security instrument requires you to occupy the property as your principal residence within 60 days after signing and to continue occupying it for at least one year after the date of occupancy, unless the lender agrees otherwise in writing or extenuating circumstances beyond your control exist.

Intent matters. If you sign an occupancy certification while planning to rent out every unit, that is occupancy fraud, which can lead to the loan being called due and to federal criminal liability. If life genuinely changes after you move in (a job transfer, for example), talk to your lender and keep records.

A Worked Example: Fourplex

Say you buy a hypothetical $400,000 fourplex with an FHA loan at 3.5% down ($14,000) and finance $386,000 at 7% over 30 years, giving a principal and interest payment of about $2,568. Add $400 in property taxes, $150 insurance, $200 utilities, and $300 budgeted maintenance, and total monthly outlay is roughly $3,618. You live in one unit and rent the other three at $1,200 each, bringing in $3,600. Your net housing cost is about $18 per month, compared with $1,500 for a comparable rental.

Two honest caveats. This simplified model excludes FHA mortgage insurance premiums, which add both an upfront charge and a monthly amount, and it assumes full occupancy of the rented units. A fourplex also has to pass the self-sufficiency test: at $1,200 per unit, net rent for the test is $4,800 × 75% = $3,600, which is less than the payment once taxes, insurance, and mortgage insurance are added, so this particular building would likely fail FHA's test unless rents are higher or you put more down. Run that check before you fall in love with a triplex or fourplex.

A Worked Example: Duplex, From Purchase to Sale

Duplexes are not subject to the self-sufficiency test, which makes them the most common first house hack. Here is a hypothetical one followed all the way through. All numbers are illustrative.

Year one: living in one unit

• Price: $400,000. Two identical units; the other unit rents for $1,900 a month.
• FHA loan: 3.5% down ($14,000), base loan $386,000 at an assumed 6.5% for 30 years. Principal and interest: about $2,440.
• Property taxes $400, insurance $150, and an illustrative $175 monthly mortgage insurance premium: total payment about $3,165.
• Maintenance reserve $200 and owner-paid water and trash $100: all-in monthly cost about $3,465.
• Net housing cost: $3,465 - $1,900 = $1,565 a month, versus $1,900 to rent an identical unit. Savings: $335 a month, about $4,020 a year.
• Principal paid down in year one: about $4,314. Together with the rent savings, roughly $8,300 of first-year benefit on a $14,000 down payment, before closing costs, vacancies, or appreciation.
• Qualifying: the lender may count 75% of $1,900 = $1,425 a month of rental income toward your effective income.

That is a real but modest win, which is typical of a duplex. It is not free housing, and one month of vacancy on the other unit ($1,900) erases almost six months of savings.

After moving out: both units rented

Suppose you move out after two years and rent your unit for $1,900 too. Income is $3,800 against costs of about $3,465, leaving roughly $335 a month before vacancy and capital repairs. Allowing 5% vacancy ($190) cuts that to about $145. The property works as a long-term hold because tenants are paying down the loan, but the cash flow is thin. Compare the numbers with the ROI calculator before treating it as income.

The Exit: Section 121 When You Move Out and Sell

The home-sale exclusion in IRC § 121 lets you exclude up to $250,000 of gain ($500,000 for married couples filing jointly when both meet the use test) if you owned and used the home as your main home for at least two years in the five years ending on the date of sale. A house hack complicates that in three ways:

1. The rental unit never qualifies. IRS Pub. 523 lists “a duplex in which you lived in one unit and rented the other” as an example of a separate portion used for rental, and Treas. Reg. § 1.121-1(e) requires you to allocate basis and sale price between the residential and rental portions. Gain on the units you never lived in is taxable.
2. Depreciation is always taxed. Under § 121(d)(6), the exclusion does not cover gain equal to depreciation allowed or allowable after May 6, 1997. That includes depreciation on your own unit after you converted it to a rental. It is taxed as unrecaptured § 1250 gain at a federal rate of up to 25%.
3. The clock runs out. If you lived in your unit for two years, you have about three years after moving out to sell and still meet the two-out-of-five test for that unit. Rental use after your last day of residence, within the five-year window, is not “nonqualified use” under § 121(b)(5)(C)(ii)(I), so renting it out in the meantime does not reduce the exclusion.

The duplex example at sale

Continuing the hypothetical: you lived in unit A for years one and two while renting unit B, then rented both for years three and four, and sell at the end of year four for $520,000. Selling costs of 6% leave an amount realized of $488,800. Assume 20% of the price was land, so the building cost $320,000, and the units are identical, so price and basis split 50/50 ($244,400 realized and $200,000 basis per unit). Depreciation is simplified to straight-line over 27.5 years, ignoring the mid-month convention and purchase closing costs.

• Unit B (always rented): depreciation $160,000 ÷ 27.5 × 4 years = about $23,273. Adjusted basis $176,727; gain about $67,673. None of it is excludable: about $23,273 is unrecaptured § 1250 gain and $44,400 is long-term capital gain.
• Unit A (your home for two years, then rented): depreciation $160,000 ÷ 27.5 × 2 years = about $11,636. Adjusted basis $188,364; gain about $56,036. You lived there two of the last five years, so § 121 applies to this unit, but the $11,636 of depreciation stays taxable. The remaining $44,400 is excluded.

Taxable gain totals about $79,309 ($67,673 + $11,636), of which about $34,909 is unrecaptured § 1250 gain. If you waited until year six to sell, unit A would likely fail the two-out-of-five test and its $44,400 of appreciation would become taxable too. Depending on income, the 3.8% net investment income tax and state income tax may also apply.

To model this for your own property, use the keep-or-sell rental property calculator and turn on its former-home mode (“This was my home”), entering the years you lived there. It shows when your exclusion window closes and compares selling with holding or a 1031 exchange. For a multi-unit house hack, enter the share of the property that was your home (for example 50% for one side of a duplex). The calculator then depreciates the rental units from purchase, applies the exclusion only to your unit’s share of the gain, and taxes the rest as an ordinary rental sale. A CPA should confirm the allocation, which must match the method you used for depreciation. If you want to defer tax on the rental portion, a 1031 exchange may be possible for that part; get professional advice before listing, because the exchange has to be set up before closing.

What Makes a Good House Hack Market

The strategy works best where unit rents are high relative to purchase prices, so a $700,000 duplex in a high-cost metro often hacks worse than a $350,000 triplex in a secondary market. When comparing candidate properties in the calculator, watch the housing cost reduction percentage rather than the absolute dollar figure, and stress-test the deal at one vacant unit. A property that still beats your current rent with one unit empty is a resilient hack; one that only works at full occupancy is a bet on everything going right in year one, which is also the year you are learning to be a landlord.

Common Mistakes

• Leaving out mortgage insurance. On a low-down-payment loan it can add hundreds of dollars a month.
• Assuming 100% occupancy. Budget for vacancy and turnover on every rented unit.
• Ignoring the self-sufficiency test on an FHA triplex or fourplex until the appraisal comes back.
• Living next to tenants without systems. Use a written lease, documented move-in inspection, and consistent screening criteria. Owner-occupied buildings of four units or fewer are exempt from parts of the federal Fair Housing Act, but not from its advertising rules, and state or local laws may still apply. See the fair housing cheat sheet.
• Missing the § 121 window. Moving out starts a roughly three-year clock on the exclusion for your unit. Put the date in your calendar.
• Forgetting depreciation. You owe tax on depreciation allowed or allowable whether or not you claimed it, so claim it on the rental units every year.

Related Resources

Read the house hacking calculator guide for more on each input, the first-time landlord playbook for setting up the rental side, and the lease agreement template and tenant screening checklist before you sign your first tenant. For the tax side, see the tax strategy guide.

This page is general information, not tax, legal, or lending advice. Tax rules and loan program requirements change; consult a CPA or tax attorney about the sale of any home you have rented, and confirm current loan terms with a licensed lender.