House Hack Break-Even Calculator
Example: Mortgage loan amount: 450000 $ · Mortgage interest rate: 6.75 %/yr · Loan term: 30 yrs · Monthly rental income from unit/room: 1400 $ · Monthly rental expenses (vacancy, repairs, insurance add-on): 150 $
| Your effective monthly housing cost | $1,669 |
| Rental income covers this % of mortgage | 42.83% |
| Months shaved off loan by applying rent | 193 |
| Rental income collected until payoff | $208,750 |
Worked example
On a $450,000 loan at 6.75%, the full mortgage payment is $2,919/month. Renting a unit for $1,400 with $150 in expenses yields $1,250 net. Applied to the mortgage, your effective housing cost drops to $1,669/month — 43% covered by the tenant. Applied as extra principal, the loan pays off in about 200 months instead of 360 — saving 160 months. Over that accelerated payoff period, you collect roughly $250,000 in net rental income.
Frequently asked questions
Is house hacking legal in my area?
Zoning laws, HOA rules, and local rental regulations vary significantly. Many cities allow accessory dwelling units (ADUs) or room rentals but may require permits, safety inspections, or landlord registration. Check your local zoning ordinance and HOA documents before renting out any portion of your home.
What tax implications come with house hacking?
Rental income is taxable, but you can deduct a proportional share of mortgage interest, property taxes, insurance, repairs, and depreciation on the rented portion. The rules around home-office-style allocations apply. Consult IRS Publication 527 (Residential Rental Property) or a CPA for the specific treatment.
What happens to my mortgage if rental income stops?
Your full contractual mortgage payment is still due regardless of rental income. The house hack strategy reduces your effective cost but does not reduce your legal obligation. Maintain 3–6 months of full mortgage payments in reserve in case the unit goes vacant or needs major repairs.