Buying a duplex, triplex or fourplex and living in one unit? Enter the price, loan and rents to see what your housing really costs once the other units pay rent, how much you save versus renting, and how the numbers change over the years.
Last updated:
Property & loan
$
%
FHA allows 3.5% on 1–4 unit owner-occupied homes.
%
$
Monthly & yearly costs
$/ yr
$/ yr
% / yr
Annual rate on the loan; FHA's annual MIP is 0.55% for most loans. Use 0 with 20%+ down.
$/ mo
$/ mo
Owner-paid water, trash, common electric.
% of rent
%
%
0 if you manage it yourself.
Rents
$/ mo
$/ mo
Used for the move-out scenario.
$/ mo
Comparable apartment if you didn't buy.
Projection
% / yr
% / yr
% / yr
Enter your values to see the result.
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How to use the House Hacking Calculator
Enter the price, unit count and loan: down payment, rate, term and closing costs.
Add yearly taxes and insurance, mortgage insurance, HOA and the utilities you pay.
Enter the rent for each unit you rent out and what you would pay to rent elsewhere.
Calculate to see your net housing cost and monthly savings.
Check the projection to see how rising rents and loan paydown change the picture.
House hacking formulas
PITI = principal & interest + property tax + insurance (+ mortgage insurance and HOA)
Rent collected = rent per unit × rented units × (1 − vacancy %)
Net housing cost = PITI + utilities + maintenance + management − rent collected
Savings vs renting = rent you would pay elsewhere − net housing cost
Return on cash from savings = annual savings ÷ (down payment + closing costs)
FHA self-sufficiency (3–4 units): 75% × total rent of all units ≥ PITI
Example: a duplex with an FHA loan
A $520,000 duplex with 3.5% down at 6.75% for 30 years has a principal and interest payment of about $3,255. Adding $517 of tax, $200 of insurance and about $230 of FHA mortgage insurance brings PITI to roughly $4,200. If the other unit rents for $1,850 (about $1,758 after 5% vacancy) and you budget $250 for utilities and 10% of rent for maintenance, your net housing cost is around $2,880 per month. That is more than the $1,900 apartment in this example, which is common in expensive markets right after purchase. Rising rents, a larger rented share (triplex or fourplex) or a lower price can flip the result.
Duplex vs triplex vs fourplex
Property
Rented units while you live there
What to watch
Duplex
1
Easiest to finance and manage; rent covers a smaller share of the payment.
Triplex
2
FHA self-sufficiency test applies; more income to offset costs.
Fourplex
3
Largest rent share under residential lending; higher insurance and upkeep.
Single-family + rooms or ADU
1+ rooms or an ADU
Check local rules for renting rooms or accessory units.
Tips before you buy
Use real lease amounts or local rent listings, not the seller's best case.
Ask your lender how much of the expected rent they will count toward qualifying.
Remember you become a landlord: screening, repairs and local tenant law are part of the deal.
Run the move-out scenario. A deal that cash-flows once you leave keeps paying off for years.
Frequently asked questions
What is house hacking?
House hacking means buying a small multifamily property (or a home with a rentable room or unit), living in part of it and renting out the rest. The rent from tenants offsets or covers your mortgage, so your own housing cost drops, and you can often use owner-occupied financing with a smaller down payment.
How is the net housing cost calculated?
Net housing cost = mortgage principal and interest + property tax + insurance + mortgage insurance + HOA + owner-paid utilities + maintenance and management − rent collected after vacancy. If the result is negative, the tenants cover everything and you keep the difference.
Can I use an FHA loan to buy a duplex, triplex or fourplex?
Yes. FHA loans allow 1–4 unit properties with as little as 3.5% down if you live in one unit as your primary residence. For 3- and 4-unit properties FHA also requires a self-sufficiency test: 75% of the expected rent from all units, including yours, must be at least the full monthly payment (PITI).
How long do I have to live in the property?
Owner-occupied loans such as FHA and conventional primary-residence mortgages generally require you to move in within about 60 days and intend to live there for at least one year. After that you can usually move out and keep the loan. Check your own loan documents.
What should I budget for maintenance and vacancy?
Many investors set aside about 5% to 10% of rent for repairs and another 5% to 10% for big replacements such as roofs and water heaters, plus 5% or so for vacancy. Older buildings usually need more. This calculator lets you set both.
Does the calculator include equity and appreciation?
Yes, the projection table shows equity each year: the estimated home value at your appreciation rate minus the remaining loan balance. The main result focuses on monthly cash costs, because equity is not spendable until you sell or refinance.
Is the money I save taxable?
Rent from the other units is rental income and must be reported, but you can usually deduct the rental share of mortgage interest, taxes, insurance, repairs and depreciation. This calculator works before income tax; ask a tax professional for your situation.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.