House Hacking Calculator
Calculate your true housing cost when tenants pay part of your mortgage. Model duplex, triplex, and fourplex strategies with FHA 3.5% down, the self-sufficiency test, live-in flip, and a 5-year wealth accumulation plan.
Duplex vs triplex vs fourplex — more units mean more income but also more price, management, and FHA qualifying complexity.
Year-by-year house hacking financial projection: equity buildup, cash flow, and net worth growth.
| Year | Home Value | Mortgage Bal. | Equity | Rental Income | Cash Flow | Cum. CF |
|---|---|---|---|---|---|---|
| 1 | $465,750 | $422,944 | $42,806 | $25,832 | -$22,478 | -$22,478 |
| 2 | $482,051 | $418,071 | $63,981 | $26,607 | -$21,703 | -$44,181 |
| 3 | $498,923 | $412,858 | $86,065 | $27,406 | -$20,905 | -$65,086 |
| 4 | $516,385 | $407,282 | $109,103 | $28,228 | -$20,083 | -$85,169 |
| 5 | $534,459 | $401,319 | $133,140 | $29,075 | -$19,236 | -$104,405 |
How to Use This House Hacking Calculator
House hacking means buying a multi-unit property (duplex, triplex, or fourplex), living in one unit, and renting out the others to offset — or even eliminate — your mortgage payment. This calculator shows you exactly how much your tenants reduce your housing cost.
Quick Calculator
Enter your Property Price, Down Payment (as low as 3.5% with FHA), Interest Rate, Number of Units, and estimated Rental Income from the other units. The result shows your effective monthly housing cost after rental income, and whether you could live for free.
Advanced Analysis
The Strategy Comparison tab compares duplex vs triplex vs fourplex at the same per-unit price. The FHA House Hack tab shows the 3.5% down FHA option, including the self-sufficiency test for 3-4 unit properties. The Live-In Flip tab models buying, renovating while living there, and selling tax-free after 2 years.
Professional Simulator
The 5-Year Plan shows year-by-year equity, cash flow, and home value growth with the FHA repeat strategy. The Tax Benefits tab calculates depreciation and expense deductions on the rented portion. The Wealth Accumulation tab compares house hacking wealth vs renting and investing.
House Hacking Formulas
Rental Income (Effective) = Gross Rent × (1 − Vacancy Rate)
Living for Free = Rental Income ≥ Total Monthly Housing Costs
FHA Self-Sufficiency (3-4 units): 75% × Gross Rents ≥ PITI Payment
The key insight: your mortgage payment is fixed, but rental income reduces your out-of-pocket cost. On a duplex, a tenant might pay $1,500/month toward your $2,200 mortgage — making your effective housing cost $700/month. On a fourplex with strong rents, you might live for free and even generate positive cash flow.
Example: First-Time House Hacker in Indianapolis
Kevin's Duplex House Hack
Kevin, 27, bought a duplex in Indianapolis for $380,000 with 3.5% FHA down. He lives in the top unit and rents the bottom unit.
| Purchase price | $380,000 |
| FHA down payment (3.5%) | $13,300 |
| Loan amount + MIP | $373,345 |
| Monthly mortgage (P&I) | $2,470 |
| Monthly MIP | $265 |
| Taxes + insurance | $500/mo |
| Rental income (bottom unit) | $1,800/mo |
| Kevin's effective cost | $1,435/mo |
| Market rent for same space | $1,600-$1,900/mo |
Kevin is paying less per month than he would to rent a comparable unit, AND building equity. After 2 years, he buys a triplex with another FHA loan and rents out both units of the original duplex — now cash-flow positive on property 1 while his triplex tenants cover most of property 2's mortgage.