How Much House Can You Actually Afford?
The number a mortgage lender will approve you for and the number you can comfortably afford are often not the same. Lenders approve based on your ability to repay, not your ability to live comfortably, save for retirement, and handle unexpected expenses at the same time.
This calculator uses two frameworks to give you an honest answer: the lender's qualification criteria and the financial planner's recommendation. Both matter. The gap between them is where most first-time buyers get into trouble.
The 28/36 Rule: The Most Widely Used Framework
The 28/36 rule has been the standard affordability guideline in American mortgage lending for decades. It works like this:
28% rule: Your total monthly housing costs, including principal, interest, property taxes, and homeowners insurance (abbreviated PITI), should not exceed 28% of your gross monthly income.
36% rule: Your total monthly debt payments, including the new mortgage plus all existing debts (student loans, car loans, credit cards, personal loans), should not exceed 36% of your gross monthly income.
Lenders may approve loans up to 43-45% of gross income for the debt-to-income ratio (the back-end ratio), especially for borrowers with strong credit scores and substantial down payments. But approval does not equal affordability. A household paying 43% of gross income toward debt has very little room for savings, emergencies, or the ongoing costs of homeownership.
The Consumer Financial Protection Bureau identifies 43% as the maximum debt-to-income ratio for a "qualified mortgage" under most lending rules. Staying meaningfully below that threshold is what distinguishes a house you can own from a house that owns you.
What the Monthly Payment Actually Includes
Many buyers focus only on principal and interest when estimating their payment. The true monthly cost is higher.
Principal and interest (P&I): The base payment determined by loan amount, interest rate, and term. This is what the calculator's amortization math produces.
Property taxes: Typically 1-1.5% of the home's value per year, collected monthly into escrow. On a $350,000 home, this adds $292-$438 per month. Rates vary significantly by state and county. New Jersey and Illinois have some of the highest effective property tax rates in the country. Hawaii and Alabama have among the lowest.
Homeowners insurance: Roughly 0.5-1% of the home's value per year. On a $350,000 home, expect $145-$290 per month.
PMI (Private Mortgage Insurance): Required on conventional loans when your down payment is less than 20%. Typically 0.5-1.5% of the loan amount per year. On a $320,000 loan, this adds $133-$400 per month. PMI drops off once you reach 20% equity.
HOA fees: If applicable for condos, townhomes, or planned communities. Can range from $100 to $1,000+ per month depending on the community.
Maintenance and repairs: Not a monthly payment, but a real and often underestimated cost. Financial planners commonly use 1% of the home's value per year as a maintenance budget. On a $350,000 home, that is $3,500 per year, or $292 per month on average. Older homes or those with aging systems (roof, HVAC, plumbing) should budget higher.
The True Cost of a Mortgage Over 30 Years
The sticker price of a home and what you actually pay are very different numbers. Interest charges on a 30-year mortgage can cost more than the original purchase price.
| Home Price | Down Payment | Loan Amount | Rate | Monthly P&I | Total Paid Over 30 Years | Total Interest |
|---|---|---|---|---|---|---|
| $300,000 | 20% ($60,000) | $240,000 | 6.5% | $1,517 | $546,120 | $306,120 |
| $300,000 | 10% ($30,000) | $270,000 | 6.5% | $1,707 | $614,520 | $344,520 |
| $400,000 | 20% ($80,000) | $320,000 | 6.5% | $2,023 | $728,280 | $408,280 |
| $500,000 | 20% ($100,000) | $400,000 | 7.0% | $2,661 | $957,960 | $557,960 |
These numbers are sobering but not a reason to avoid homeownership. They are a reason to understand exactly what you are committing to before you sign.
A 15-year mortgage roughly halves the total interest paid compared to a 30-year mortgage, at the cost of a higher monthly payment. At a 6.5% rate on a $240,000 loan, a 30-year mortgage costs $306,120 in interest. A 15-year mortgage on the same loan costs approximately $128,000 in interest, a savings of $178,000, though the monthly payment rises from $1,517 to $2,092.
Down Payment: How Much Is Actually Needed?
The conventional wisdom of "20% down" exists because it eliminates PMI and results in a lower monthly payment. But 20% is not a requirement.
3% down: Available on conventional loans (Fannie Mae HomeReady and Freddie Mac Home Possible programs) for first-time buyers and qualifying income levels.
3.5% down: FHA loans accept 3.5% down with a credit score of 580 or above. FHA loans carry mortgage insurance premiums (MIP) for the life of the loan if you put down less than 10%.
0% down: VA loans (for veterans and active military) and USDA loans (for qualifying rural properties) require no down payment and no mortgage insurance.
20% down: Eliminates PMI, reduces the loan balance, and results in the lowest ongoing payment. Worth targeting if achievable without depleting your emergency fund.
One important caveat: do not drain your savings to reach a larger down payment. Arriving at closing with a 20% down payment but zero emergency fund leaves you immediately vulnerable to the repair costs that inevitably come with homeownership.
Hidden Costs of Buying That First-Timers Often Miss
Closing costs: Typically 2-5% of the loan amount, paid at closing. On a $300,000 purchase with a $240,000 loan, expect $4,800 to $12,000 in closing costs. These include loan origination fees, appraisal, title insurance, escrow fees, and prepaid taxes and insurance.
Moving costs: $1,000 to $5,000+ depending on distance and volume.
Immediate repairs and updates: Most buyers spend $5,000 to $20,000 in the first year on items the home inspection flagged or improvements they wanted to make.
Utility cost changes: Heating and cooling a house costs more than heating and cooling an apartment. Budget for this difference.
Furniture: A larger home typically means more rooms to furnish. This cost sneaks up on buyers who moved from smaller spaces.
When Renting Is the Better Financial Choice
Buying a home is not always the right financial decision, even for people who can afford to. The calculator shows you whether the numbers work. The decision also depends on:
Time horizon. The break-even point between renting and buying is typically 5-7 years in most U.S. markets, accounting for transaction costs, mortgage interest front-loading, and opportunity cost of the down payment. If you expect to move in 3 years, buying is often the more expensive option even if monthly ownership costs are lower than rent.
Local price-to-rent ratio. In cities where home prices are very high relative to rents (San Francisco, Manhattan, much of coastal California), renting and investing the difference in a diversified portfolio has historically outperformed buying for many time horizons. In markets with moderate prices and rising rents (much of the Midwest and South), buying typically wins.
Flexibility value. Renters can move quickly for career opportunities, family needs, or lifestyle changes. Homeowners cannot. This flexibility has real economic value that is hard to quantify but should be considered.
Real-World Examples
Example: James and Kelly, 31, dual income household
Situation: Combined gross income of $115,000/year. They have $45,000 saved for a down payment and $18,000 in other debts (car loan and student loans). Monthly debt payments: $620.
What they calculated: At 28% of gross income, their maximum PITI is $2,683/month. At 36%, the combined debt ceiling is $3,450, leaving $2,830 for housing after their $620 in other debt payments.
Result: At a 6.75% rate with 10% down, they can comfortably afford a home in the $330,000-$360,000 range. Their local market has median prices of $310,000. They are in good shape.
Example: Dana, 28, buying solo
Situation: Gross income $72,000/year ($6,000/month). Student loan payments $380/month. Car loan $290/month. Saved $25,000.
What she calculated: 28% rule allows $1,680/month for PITI. 36% ceiling allows $2,160 total debt, minus $670 in existing payments, leaves $1,490 for housing. The more restrictive limit is $1,490.
Result: At 6.75% with 8% down, $1,490/month supports a loan of roughly $215,000. With an $18,000 down payment on a $233,000 purchase, she needs to stay under $235,000. She can buy in her market but has limited options in high-cost neighborhoods.
The Most Common Affordability Mistake
The most common mistake is calculating affordability using gross income without accounting for taxes, retirement contributions, health insurance, and other payroll deductions. If you earn $8,000 per month gross but take home $5,500 after all deductions, a mortgage payment that is 28% of your gross income ($2,240) represents 40% of your take-home pay. That is a genuinely tight budget.
Always sanity-check the mortgage payment against your take-home pay. A monthly housing payment exceeding 35% of net take-home pay, after taxes and deductions, leaves limited room for savings, emergencies, and the ongoing costs of ownership.
This calculator is for educational and informational purposes only and does not constitute financial or mortgage advice. Mortgage rates, property tax rates, and insurance costs vary significantly by location and borrower profile. Contact a licensed mortgage lender for a personalized pre-approval.
