House Hacking Calculator

Compare two common paths: (1) rent and invest your cash or (2) buy a home, live in it for a while, offset some of the cost with roommate or partner income, then either keep it as a rental or sell later. This tool is meant for “buy now, maybe rent later” decisions — not just plain rent-vs-buy.

Inputs

Calculated monthly mortgage payment (P&I)

Computed from purchase price, down payment, rate, and loan term.

Estimated year-1 total owner monthly cost

Mortgage payment + property tax + HOA + repairs, before offsets.

Calculated cash needed to buy

Down payment + buyer closing costs.

Calculated initial stock amount in rent path

Cash kept invested instead of used to buy.

Property

Purchase price

Down payment (% of purchase price)

Buyer closing costs (% of purchase price) ?

Selling cost (% of sale price) ?

Mortgage rate (%)

Mortgage term (years)

Living Assumptions

Monthly rent if you choose not to buy

Years living in the property

House-hacking income while living there (roommate / partner / ADU)

Monthly market rent after moving out

Growth Assumptions

Home appreciation (%) ?

Stock return (%) ?

Rent inflation (%)

Ownership Costs

Owner cost inflation (%)

Property tax (% of home value) ?

Monthly HOA ?

Repairs / capex (% of property value annually)

Property management (% of rent)

Vacancy (% of rent) ?

Marginal tax rate (%) ?

Rental tax benefit (%) ?

Additional cash kept invested in rent path ?

Max year shown

Also show “hold forever” comparison at the selected horizon

Defaults are set to generic U.S. assumptions rather than one specific city or personal scenario. If you know your market, update the mortgage rate, property tax, HOA, expected rent, and appreciation assumptions before relying on the result. Hover over the small ? icons for explanations of less obvious inputs.

Break-even sale year

—

Best sale year for buying

—

Advantage at year 15

—

Buy minus rent

Hold-forever advantage at horizon

—

No selling costs applied in this view.

Year-1 monthly cost gap

—

Buy monthly cost minus rent monthly cost during owner-occupancy.

Net ending position by sale year

These lines assume you sell in that year. The buy path includes selling costs in this chart.

Buying advantage by sale year

Above zero means buying is ahead if you sell in that year. Below zero means renting is ahead.

Selected checkpoints

Year	Rent path	Buy path if sold	Buy − rent

“Hold forever” is shown separately in the summary card and means comparing both paths at the selected horizon without forcing a sale of the property.

How to read the outputs

Rent path means you keep the would-be down payment and closing costs invested, pay rent during the years you would have lived in the property, and then stop the housing comparison after that owner-occupancy window.
Buy path if sold includes down payment, closing costs, mortgage payments, property tax, HOA, repairs, house-hacking income while living there, rental cash flow after moving out, and selling costs in the selected year.
Break-even sale year is the first year where buying comes out ahead if you sell in that year.
Best sale year is the year where the buy-minus-rent gap is largest under the current assumptions.
Hold-forever advantage removes selling costs and compares both paths at the final horizon, which is useful if you might keep the property indefinitely.
Use this tool directionally. Small changes to appreciation, rent growth, vacancy, and stock returns can change the result a lot.

Year-1 monthly cash flow breakdown

Line item	Rent path	Buy path

This is a sanity-check view for the first year only. It helps explain why the model prefers renting or buying before long-term appreciation and sale-year effects kick in.