House hacking calculator

House hacking means buying a small rental, such as a duplex or a house with spare rooms, living in one part and renting out the rest. Enter the price, the loan, the monthly costs and the rent from the other units. The results show what living there costs you each month once the rent is in, how that compares with what you pay to live now, and the cash flow if you later move out and rent your unit too.

Your results

Estimate

Your monthly housing cost after rent: $1,415.33

Saved each month against what you pay now: $334.67
Monthly loan payment: $2,275.33
Total monthly costs: $3,125.33
Rent collected after vacancy (monthly): $1,710.00
Share of the costs the rent covers: 54.71%
Monthly cash flow if you move out and rent your unit: $294.67
Cash needed to buy: $27,000.00

That is $334.67 a month less than you pay to live now.
Owner-occupied loans usually ask you to live in the property for a set time. Check the terms with your lender.

Results are estimates for planning only. They are not legal, tax or investment advice, and they apply no state or local rules. Check your lease, your local laws and a qualified professional before you rely on a number.

How the house hacking numbers are calculated

Your housing cost after rent = (loan payment + taxes and insurance + other costs) - rent from the other units x (1 - vacancy rate)

The monthly costs are the loan payment (principal and interest on the price less the down payment), property taxes and insurance, and the other costs of running the building: repairs and reserves, utilities you pay and any HOA dues. The calculator counts every cost for the whole property, your unit included.

The rent comes from every unit or room except yours, less an allowance for the months a unit sits empty. Monthly costs minus that rent is what living there costs you. Compare it with what you pay to live now to see the monthly saving. When the rent is larger than the costs, the result is negative: the tenants cover your housing with money left over.

Moving out turns the property into a full rental. The move-out figure adds the rent your unit would bring to the other units' rent, takes off the same vacancy allowance and subtracts the same monthly costs. The rental cash flow calculator breaks that cash flow down line by line, with management and other income.

Worked example

A duplex costs $360,000 with 5% down and $9,000 of closing costs. The loan is at 7% over 30 years. Taxes and insurance come to $550 a month and repairs, utilities and other costs to $300. You live in one unit and rent the other for $1,800 a month, allowing 5% for vacancy. Your unit would also rent for $1,800, and you pay $1,750 a month to live where you are now.

Down payment: $360,000 x 5% = $18,000. Loan: $360,000 - $18,000 = $342,000. Cash needed to buy: $18,000 + $9,000 = $27,000.
Monthly loan payment on $342,000 at 7% over 30 years: $2,275.33.
Monthly costs: $2,275.33 + $550 + $300 = $3,125.33.
Rent collected: $1,800 x 95% = $1,710.
Your housing cost after rent: $3,125.33 - $1,710 = $1,415.33 a month, which is $1,750 - $1,415.33 = $334.67 less than you pay now.
If you move out and rent both units: ($1,800 + $1,800) x 95% = $3,420, less $3,125.33 of costs, is $294.67 a month of cash flow.

Living in the duplex costs $1,415.33 a month after the rent comes in, $334.67 a month less than you pay now, and the rent covers 54.71% of the costs. Renting both units after you move out gives a cash flow of $294.67 a month.

Frequently asked questions

What is house hacking?

House hacking is buying a property with more space than you need, living in part of it and renting out the rest, so the rent pays some or all of your housing costs. A duplex, triplex or fourplex with one unit for you is the common setup, and renting spare rooms in a single-family house works the same way.

How does the calculator work out my housing cost?

It adds up the monthly costs of the whole property and takes off the rent the other units bring in after vacancy. In the example, $3,125.33 of costs less $1,710 of rent leaves $1,415.33 a month, which is what living there costs you.

Can I use the calculator for renting out rooms?

Yes. Enter the total monthly rent from the rooms you rent out, and leave out the room you live in. Check your local rules, your HOA and your insurance before you rent rooms in your home, since some places limit how many unrelated people can share a house.

What loan can I use to house hack?

Many buyers use an owner-occupied mortgage, which often allows a smaller down payment than a loan for an investment property. These loans usually ask you to move in within a set time and live there for a period, often at least a year. Ask your lender about the terms, the down payment and whether the expected rent counts toward qualifying.

What happens when I move out?

The property becomes a full rental, and your unit's rent joins the rest. The move-out figure shows that cash flow with the same costs: in the example, $3,420 of rent after vacancy less $3,125.33 of costs is $294.67 a month. Check whether your loan's occupancy terms allow the move first.

Collect rent from the units you rent out

KeyRing drafts each month's rent invoices for you to approve, tenants pay online by bank transfer or card, and the dashboard shows what was billed, paid and overdue. Your first subscription starts with a 14-day free trial.

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