House Hack Calculator - Free tool to analyze your house hack

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House Hack Calculator

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House Hack Calculator

Use Bellhaven's house hacking calculator to analyze small multifamily and rent-by-the-room properties and see whether tenants can cover your mortgage. Enter your purchase price, expected rents, and monthly PITI to instantly see your effective housing cost vs. your current rent, projected cash flow, cap rate, and whether the deal meets the 1% rule, DSCR, and other benchmarks investors and lenders use.

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🏠 Property & Units

1 unit = single-family, rent by the room. 2–4 units = small multifamily.

Purchase Price

list price or your offer

Down Payment

5.0% of price

Number of Units

Monthly Rent — per unit

🏘️ Rename each unit (e.g. "Upstairs", "1B")

YOU

You'll live in

Its rent is excluded from income

💰 Monthly Costs & Reserves

Your mortgage, the reserves pros budget for, and anything you pay that tenants don't.

🏦 Mortgage Payment (PITI)

Your full monthly bill from the lender.

Total Monthly Payment

principal + interest + tax + insurance

Need help calculating your payment? Click here

🛟 Operating Reserves & Vacancy

What's left after vacancy, repairs, and management. Tap ⓘ for typical ranges.

Vacancy

% of rent

CapEx Reserve

% of price / yr

Maintenance

% of rent

Property Mgmt

% of rent

🔌 Owner-Paid Expenses

Costs tenants don't cover — shared utilities, trash, lawn, snow, pest, HOA. Ask the seller for 12 months of actual bills.

Owner-paid total: $75/mo

💭 Your Current Situation — the bar to beat

The bar is what you pay today. If owning + house hacking gets you at or below it, you're winning — tenants pay down your mortgage either way.

Your Current Monthly Rent

Current Utilities You Pay (optional)

What you pay now$1,950/mo

📊 House Hack Analysis

Your effective housing cost

$1,129/mo

vs current housing

$1,950/mo

🎉 You save $821/mo vs your current housing

Tenants subsidize your housing — plus you build equity through principal paydown.

Rent from Other Units

+$3,000/mo

From 2 rented units

Reserves & Owner Costs

−$1,029/mo

CapEx + vacancy + maintenance + mgmt + utilities

Mortgage (PITI)

−$3,100/mo

Your full housing payment

🎉 Your tenants subsidize $3,000/mo of your housing. You pay less than renting AND build equity.

Deal scorecard (fully rented)

1% Rule

1.08%

✅ Above $4,250/mo target

50% Rule

29%

✅ Operating expenses in check

Cap Rate

9.18%

🔥 Strong yield

GRM

7.7

Lower is better — solid

Cash Flow

$151/mo

After you move out & rent all units

Per-Door Cash Flow

$50/mo

Below $100/door rule of thumb

Cash-on-Cash

5.3%

Annual return on $34,000 invested

DSCR

1.05

Tight — covers debt only

📚 Real Estate 101 — The Rules Investors Live By

🏠House Hacking

You live in one unit of a 2–4 unit property and rent the others. Tenants help (or fully) cover your mortgage. Bonus: you can use a low-down-payment owner-occupant loan (3.5% FHA, 5% conventional) instead of 20–25% down for an investment property.

🛏️Rent by the Room

A flavor of house hacking on a single-family home: you live in one bedroom and rent out the others (often furnished, often mid-term). It can dramatically out-earn renting the whole house to one family — three rooms at $700 beats one tenant at $1,800. Trade-off: more turnover and you share common space.

🎯The 1% Rule

Monthly rent should be at least 1% of the purchase price. A $300K duplex needs ≥ $3,000/mo total rent. It's a quick filter — pass = likely to cash flow, fail = run the full numbers carefully. Hard to find in expensive coastal markets.

✂️The 50% Rule

Roughly half of gross rent disappears into operating expenses — taxes, insurance, vacancy, maintenance, capex, management, utilities. The other half is what's left to pay the mortgage. If your numbers show opex way under 50%, you're probably forgetting something.

📈Cap Rate

Net Operating Income ÷ Purchase Price. It's the return you'd get if you paid all cash. 4–6% is typical in strong markets; 7%+ is harder to find but cash-flows better. Use it to compare deals apples-to-apples regardless of financing.

💰Cash-on-Cash Return

Annual cash flow ÷ cash you put in (down payment + closing). This is the return on YOUR money — accounting for the leverage of a mortgage. Investors typically target 8%+. Below 4% and your money may work harder elsewhere.

🏦DSCR (Debt Coverage)

Annual NOI ÷ annual mortgage payments. Lenders love this number — most want ≥ 1.25 (income is 25% above debt). Below 1.0 means rents don't cover the loan and you're feeding the property every month.

🧮GRM (Gross Rent Multiplier)

Purchase Price ÷ Annual Gross Rent. The fast-and-loose cousin of cap rate — ignores expenses. Useful for back-of-napkin comparisons. ~6–8 is excellent, 8–12 is normal, 12+ is expensive relative to rents.

🚪$100 Per Door

Old-school rule that every rented unit should clear at least $100/month after every expense (including mortgage + reserves). A fourplex should net you $400+/mo. Some investors hold out for $200/door — your call based on market.

🔧CapEx vs Maintenance

Maintenance = small ongoing fixes (leaky faucet, $200). CapEx = big-ticket replacements you save up for (roof, HVAC, water heater — $5K–$20K each). The 1%-of-price-per-year default is a rough planning number, not an exact prediction.

🔌Owner-Paid Utilities

In small multifamily, owners often pay shared services tenants can't split: water/sewer (rarely sub-metered), trash pickup, common-area electric, gas if there's only one meter, lawn, snow, pest control, HOA. Always ask the seller for 12 months of actual bills.

🏦What is PITI?

Your full monthly housing payment: Principal + Interest (the loan) + property Taxes + homeowners Insurance. Lenders usually escrow tax and insurance, so you pay one combined number monthly. PITI is what really matters when budgeting — not just P&I.

🏆The Hidden Wins

Even break-even cash flow can be a great deal. You're also getting: principal paydown (tenants build your equity), appreciation (property value grows long-term), tax benefits (depreciation), and inflation hedging (rents rise, your fixed mortgage doesn't).