How Much House Can I Afford? Free Home Affordability Calculator with 28/36 Rule & Hidden Costs
Buying a home is the largest financial decision most people make. Figuring out exactly how much house you can afford is step one. Our free home affordability calculator goes beyond simple income multipliers to give you a realistic, stress-tested budget using industry-standard rules and true ownership costs.
The 28/36 Rule: The Golden Standard for Home Affordability
Mortgage lenders primarily use the 28/36 Rule to determine your borrowing capacity. This dual-constraint rule helps ensure you aren't "house poor."
- The 28% Rule (Front-End Ratio): Your total housing costs should not exceed 28% of your gross monthly income. "Housing costs" mean PITI: Principal, Interest, Property Taxes, and Homeowners Insurance (plus HOA fees if applicable). For example, if you earn $75,000 a year ($6,250/month), your housing costs should stay under $1,750/month.
- The 36% Rule (Back-End Ratio): Your total debt obligations—which includes your new housing payment PLUS existing debts like car loans, student loans, and minimum credit card payments—should not exceed 36% of your gross monthly income.
If you have high existing debt, the 36% rule will be your limiting factor, drastically reducing the home price you can afford.
Why Your Mortgage Payment Is Only Half the Story
Many first-time buyers mistakenly look at the principal and interest payment and assume that's what owning a home costs. Hidden costs can increase your monthly payment by 40% to 50%.
A $400,000 home might have a mortgage of $2,128, but when you add property taxes, insurance, PMI, and maintenance reserves, the true cost of ownership often exceeds $2,800 a month. Our True Cost visualizer breaks this down so you aren't caught off guard.
How Much Down Payment Do You Really Need?
While 20% is the ideal down payment to avoid Private Mortgage Insurance (PMI), it is not strictly required. FHA loans allow as little as 3.5% down, and some conventional loans allow 3%.
However, putting less than 20% down triggers PMI. Our Down Payment Strategy Analyzer shows you exactly how much PMI you'll pay and when it will drop off. Sometimes, paying PMI is worth it to stop renting and start building equity, but you need to know the math first.
What Credit Score Do You Need to Buy a House?
Your credit score directly impacts two massive costs: your interest rate and your PMI rate. Generally:
- Excellent (750+): Secures the lowest interest rates and cheapest PMI.
- Good (700-749): Standard rates, moderate PMI.
- Fair (650-699): Higher interest rates and significantly higher PMI. You may need an FHA loan.
- Poor (<650): Difficult to secure a conventional mortgage; FHA is usually the only option (minimum 580 required for 3.5% down).
How Rising Interest Rates Affect Your Buying Power
Interest rates are the silent dictator of affordability. A general rule of thumb is that for every 1% increase in interest rates, your buying power decreases by about 10% (assuming you want to keep the same monthly payment).
Our Rate Shock Stress Test shows you how a slight jump in rates can knock tens of thousands of dollars off your maximum budget.
Hidden Costs Every First-Time Buyer Forgets
Don't drain your entire savings account on the down payment. You need cash for:
- Closing Costs: Typically 2% to 5% of the loan amount ($6,000 - $15,000 on a $300k home).
- Inspections & Appraisals: ~$500 to $1,000 out of pocket before you even close.
- Moving & Furnishing: Easily $2,000+.
- Immediate Repairs: Even turn-key homes need new locks, paint, or minor fixes immediately.
Why This Calculator Is 100% Private
Financial data is sensitive. Unlike other real estate sites that require your email or phone number to show you your budget (and then sell your info to mortgage brokers who call you endlessly), this tool runs 100% locally in your browser. No data is sent to any server. You can safely plan your finances in complete privacy. No signup required. No spam.