Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Your effective monthly housing cost
$1,761
Monthly saving vs renting
$139
Annual saving
$1,665
Full monthly cost of the property
$3,923
Rent collected after vacancy
$2,162
Principal & interest
$2,548
Cash flow once fully rented
-$586
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One click, a permanent link with your numbers baked in.
Got your number — what next?
Pick one, it takes 20 secondsHow to use this
- 1Enter purchase price ($).
- 2Enter down payment (%).
- 3Enter mortgage rate (%).
- 4Enter mortgage insurance ($/mo).
- 5Enter property taxes ($/mo).
- 6Enter insurance ($/mo).
- 7Enter utilities you pay ($/mo).
- 8Enter maintenance & capex reserve ($/mo).
- 9Enter units or rooms you rent out (count).
- 10Enter rent per unit or room ($/mo).
- 11Enter market rent for the space you occupy ($/mo).
- 12Enter what you pay in rent now ($/mo).
- 13Enter vacancy allowance (%).
- 14Read your your effective monthly housing cost on the right — it updates as you type.
- 15Hit Share to keep the scenario or send it to someone.
About this calculator
House hacking means buying a property, living in one part, and renting the rest — the point is not cash flow but reducing your own housing cost, often to near zero. This calculator totals the full ownership cost, subtracts the rent collected from the other units or rooms, and returns your effective monthly housing cost. It compares that against what you currently pay in rent, and shows the cost once you move out and the whole property rents, which is the figure that decides whether you have bought a good rental or just a discounted place to live.
Worked example
Using the values the calculator loads with:
Inputs
- Purchase price: 420000 $
- Down payment: 5 %
- Mortgage rate: 6.6 %
- Mortgage insurance: 210 $/mo
- Property taxes: 410 $/mo
- Insurance: 145 $/mo
- Utilities you pay: 260 $/mo
- Maintenance & capex reserve: 350 $/mo
- Units or rooms you rent out: 2 count
- Rent per unit or room: 1150 $/mo
- Market rent for the space you occupy: 1250 $/mo
- What you pay in rent now: 1900 $/mo
- Vacancy allowance: 6 %
Results
- Your effective monthly housing cost: $1,761.25
- Monthly saving vs renting: $138.75
- Annual saving: $1,665.02
- Full monthly cost of the property: $3,923.25
- Rent collected after vacancy: $2,162.00
- Principal & interest: $2,548.25
- Cash flow once fully rented: -$586.25
What each field means
Inputs
- Purchase price ($)
- The purchase price used in the calculation, measured in $. Starts at 420000 $ so you have a working example on load.
- Down payment (%)
- The down payment used in the calculation, measured in %. Starts at 5 % so you have a working example on load. Accepted range: 0–100 %.
- Mortgage rate (%)
- The mortgage rate used in the calculation, measured in %. Starts at 6.6 % so you have a working example on load.
- Mortgage insurance ($/mo)
- The mortgage insurance used in the calculation, measured in $/mo. Starts at 210 $/mo so you have a working example on load.
- Property taxes ($/mo)
- The property taxes used in the calculation, measured in $/mo. Starts at 410 $/mo so you have a working example on load.
- Insurance ($/mo)
- The insurance used in the calculation, measured in $/mo. Starts at 145 $/mo so you have a working example on load.
- Utilities you pay ($/mo)
- The utilities you pay used in the calculation, measured in $/mo. Starts at 260 $/mo so you have a working example on load.
- Maintenance & capex reserve ($/mo)
- The maintenance & capex reserve used in the calculation, measured in $/mo. Starts at 350 $/mo so you have a working example on load.
- Units or rooms you rent out (count)
- The units or rooms you rent out used in the calculation, measured in count. Starts at 2 count so you have a working example on load.
- Rent per unit or room ($/mo)
- The rent per unit or room used in the calculation, measured in $/mo. Starts at 1150 $/mo so you have a working example on load.
- Market rent for the space you occupy ($/mo)
- The market rent for the space you occupy used in the calculation, measured in $/mo. Starts at 1250 $/mo so you have a working example on load.
- What you pay in rent now ($/mo)
- The what you pay in rent now used in the calculation, measured in $/mo. Starts at 1900 $/mo so you have a working example on load.
- Vacancy allowance (%)
- The vacancy allowance used in the calculation, measured in %. Starts at 6 % so you have a working example on load. Accepted range: 0–40 %.
Results
- Your effective monthly housing cost
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Monthly saving vs renting
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Annual saving
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Full monthly cost of the property
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Rent collected after vacancy
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Principal & interest
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cash flow once fully rented
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Why can I put so little down?
Owner-occupied financing allows far lower down payments than investor loans — some government-backed programmes go to a few percent on properties up to four units, provided you actually live there for the required period. That leverage is the core advantage of house hacking, and it disappears the moment the property becomes a pure investment.
Is renting rooms the same as renting units?
Financially similar, practically very different. Rooms usually produce more rent per square foot but come with shared spaces, faster turnover, and a much thinner boundary between landlord and housemate. Separate units cost more per door and give you back your privacy.
What happens when I move out?
The post-move-out figure on this page is the answer, and it is the one to underwrite against. Plenty of house hacks work brilliantly while you occupy them and cash flow negatively the day you leave, because your unit's rent was covering costs you stopped paying attention to.
Should I count the maintenance reserve if nothing breaks?
Yes. Reserves are not a prediction of this month, they are the average of the roof, the water heater, and the turnover spread across every month. Skipping them makes the first real repair look like a catastrophe instead of a budgeted event.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Short-Term Rental Break-Even Calculator
The occupancy rate an STR needs to beat both its costs and the long-term rent it replaces.
Rental Property Cash Flow Calculator
Monthly cash flow after mortgage, vacancy, and reserves.
Rental Property Cap Rate Calculator
Net operating income over price — the unlevered yield that lets you compare any two deals.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). House Hacking Cost to Live Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/house-hack-cost-to-live
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/house-hack-cost-to-live" target="_blank" rel="noopener">House Hacking Cost to Live Calculator — RevenueLab</a> (2026).</p>
Source: [House Hacking Cost to Live Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/house-hack-cost-to-live) (2026).