House Hacking Calculator
Calculate how much rental income from house hacking reduces your effective mortgage payment. Model multi-unit, ADU, and room-renting strategies.
Reviewed for accuracy by Marcus Webb and the Blueprint Dynamics editorial team (last updated July 2026). Our calculators use primary-source formulas and are cross-checked against IRS publications, Fannie Mae guidelines, and Federal Reserve data. Learn more about our methodology.
Your Monthly Housing Cost
$204 cash flow
Tenants cover your housing!
Rental Income (2 units)
$2,800/mo
PITI Payment
$2,596/mo
Down Payment
$35,000
Cash-on-Cash ROI
7.0%
What is house hacking?
House hacking means buying a property and renting out part of it — a room, a unit, or an accessory dwelling unit — so that the rental income offsets or eliminates your mortgage payment. The goal: live for free or near-free while building equity in a property you own. It combines owner-occupant financing advantages (low down payment, better rates) with real estate investing principles. House hacking is widely considered the most accessible entry point to real estate investing because it requires no prior investing experience and uses the same financing any first-time homebuyer can access.
Common house hacking strategies
Room rental in a single-family home: buy a 3–4 bedroom home and rent 1–2 rooms. Rental income of $600–$1,200/room/month in most markets. Advantages: simplest to execute, easy to exit. Disadvantage: shared living space with tenants. Multifamily house hacking: buy a 2–4 unit property, live in one unit, rent the others. This is the most powerful structure — rent from 1–3 other units often covers or exceeds the full mortgage. A duplex with $2,200 in total rent where you live in one unit and collect $1,100 from the other reduces your effective housing cost to $1,100/month minus expenses. ADU (accessory dwelling unit): build or convert a garage, basement, or backyard cottage into a rentable unit. Requires permits and upfront investment but adds permanent equity and rental income without sharing living space.
Financing advantages of house hacking
Owner-occupant financing is significantly more favorable than investment property financing. FHA loans allow 3.5% down (vs. 20–25% for investment properties). Conventional owner-occupant loans allow 5–10% down on 2–4 unit properties. Interest rates are typically 0.5–1% lower than investment property rates. These financing advantages make the entry cost dramatically lower. On a $350,000 duplex: FHA down payment = $12,250. Investment property down payment = $70,000–$87,500. The same property, the same strategy, requires $57,000–$75,000 less cash to enter as a house hacker.
Analyzing a house hack — the key numbers
To evaluate a house hack: Total monthly housing cost = mortgage P&I + property taxes + insurance + HOA + maintenance estimate. Your effective housing cost = total housing cost − rental income. Target: rental income covers at least 75–100% of total housing cost. Worked example: $350,000 duplex. 5% down = $17,500. Loan $332,500 at 7%: P&I = $2,213. Taxes $350, insurance $150 = $500. Maintenance reserve $175. Total: $2,888/month. Unit 2 rents for $1,400/month. Your effective cost: $2,888 − $1,400 = $1,488/month. Compare to renting a comparable apartment in the same area — if that would cost $1,600–$2,000/month, you're housing-cost negative while building equity and an asset.