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House Hacking Calculator

What is your net housing cost after rent from other units or rooms?

Your numbers

Net monthly housing cost

$1,794

Effective rent from other units / rooms$1,656
Share of PITI covered by rent51.7%

Tip. Educational estimate with the assumptions listed on this page. Not tax, legal, or investment advice.

Assumptions

  • You still live in the property. This is housing cost, not a pure investment CoC.
  • Vacancy applies only to the rented portion.
  • Tax benefits of owner-occupied vs rental allocation are excluded.

Explore the numbers

Examples

Load a scenario, then change one input at a time.

Example 1

Duplex

You live in one side.

Net monthly housing cost

$1,794

Example 2

Roommates

Two rooms at $900.

Net monthly housing cost

$1,416

Example 3

House pays you

Triplex with strong rents.

Net monthly housing cost

-$148

What this calculates

Free house hacking calculator. Subtract the rent from housemates or extra units from your mortgage payment and owner costs to see what your housing really costs.

How to use it

  1. Use PITI from the mortgage tool, not a round number from memory.
  2. If you rent rooms, vacancy is roommate turnover.
  3. A negative net housing cost means the property pays you to live there — until a void month.

Common mistakes

  • Ignoring that you still need a bedroom when the tenant leaves.
  • Underwriting 100% occupancy on three rooms in a house you also occupy.
  • Forgetting utilities you agreed to cover.

Formula

Net housing = PITI + owner ops − rent × (1 − vacancy%).

FAQ

Is house hacking the same as a duplex rental?

You occupy part of it. Financing and tax treatment differ from a pure rental.

Can this be an STR on the other unit?

Yes, but then use STR occupancy and ops, not a simple vacancy percent.

Does this help with DTI?

Some lenders count a fraction of rental income. Do not assume 100% of this rent lands on the application.

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