Not Sure How Much House You Can Afford?
Lenders often approve more than you should actually borrow. Read How Much House Can You Actually Afford? The 28/36 Rule Explained to set a safe budget.
What is a Home Affordability Calculator?
A home affordability calculator helps you determine the maximum home price you can comfortably buy based on your income, existing debts, and down payment. Lenders use the 28/36 rule as a guideline to approve mortgages.
The 28/36 Rule Explained
Front-End Ratio: 28%
Your monthly housing costs (mortgage principal + interest + property tax + insurance) should not exceed 28% of your gross monthly income.
Back-End Ratio: 36%
Your total monthly debt (housing + car loans + student loans + credit cards) should not exceed 36% of gross monthly income.
Key Factors That Affect Affordability
- Annual Income: The foundation of every mortgage calculation. Higher income increases your borrowing capacity.
- Down Payment: A larger down payment reduces your loan size and may help you avoid PMI (Private Mortgage Insurance).
- Interest Rate: Even a 0.5% difference in rate can significantly change your monthly payment and max home price.
- Monthly Debts: Existing obligations like car loans or student debt reduce how much you can borrow for a home.
- Loan Term: A 15-year mortgage has higher payments but saves enormous interest. A 30-year is more affordable monthly.
How is your max home price calculated?
The calculator works backward from your income. It finds the highest monthly housing payment allowed under both the 28% and 36% limits, then solves for the home price that produces that payment — including principal, interest, property tax, insurance, and PMI if applicable.
The Two Limits
- 28% Limit= Monthly gross income × 0.28 (max housing payment alone)
- 36% Limit= (Monthly gross income × 0.36) − existing monthly debts (max housing payment after debts)
- Max Payment= Whichever of the two limits is lower
The calculator then finds the home price whose full PITI payment equals this max — that's your maximum affordable price.
How to use Finzony's home affordability calculator
Get a realistic max home price in under a minute:
- Enter your annual gross income: Use your pre-tax household income if you're buying with a co-borrower.
- Add your monthly debt payments: Car loans, student loans, and minimum credit card payments — not your future mortgage.
- Enter your down payment saved: Below 20% triggers PMI, which the calculator factors in automatically.
- Set your loan assumptions: Interest rate, loan term, property tax rate, and homeowners insurance — use quoted rates where you have them.
- Review your results: Compare the lender's maximum to the conservative recommendation, and check your ratios against lender thresholds.
Hidden Costs First-Time Buyers Miss
- Property taxes (varies by county/state)
- Homeowner's insurance (required by lenders)
- PMI if down payment is under 20%
- HOA fees in many communities
- Closing costs: 2-5% of purchase price
- Annual maintenance: budget 1-2% of home value
Why use Finzony's home affordability calculator?
- Uses the Same Rule Lenders Use: This calculator applies the actual 28/36 rule underwriters use to approve mortgages — so the number you get is realistic, not a rough guess.
- Full PITI, Not Just P&I: Property tax, homeowners insurance, and PMI are all factored into your monthly housing cost — so your max home price reflects what you'll truly pay each month.
- Two Numbers, Not One: You get both the lender's maximum and a conservative recommendation (85% of max) — because what a bank approves and what's comfortable to actually live with are often different.
- Instant Qualification Checks: See your front-end ratio, back-end ratio, and down payment percentage against lender thresholds in real time as you adjust your inputs.
Common Affordability Mistakes to Avoid
- 1. Borrowing up to the lender's maximumJust because you qualify for the full 28/36 amount doesn't mean you should spend it. The 'conservative' recommendation (about 85% of max) leaves room for savings, emergencies, and lifestyle — most first-time buyers regret maxing out.
- 2. Forgetting existing debt drags down your budgetA car payment or student loan directly reduces how much house you can afford under the 36% back-end rule. Paying down debt before house-hunting can meaningfully raise your approved amount.
- 3. Not accounting for PMI below 20% downIf your down payment is under 20%, PMI adds to your monthly housing cost and eats into your 28% housing budget — which lowers the max home price you can actually afford, not just your monthly payment.
- 4. Ignoring costs outside PITIClosing costs, moving expenses, immediate repairs, and ongoing maintenance (1–2% of home value per year) aren't part of the 28/36 calculation but hit your bank account just as hard. Budget for them separately.
The Bottom Line
The 28/36 rule gives you a realistic ceiling, not a target. Use the number this calculator produces as your starting point, then work backward from the conservative recommendation to leave breathing room in your monthly budget. Before you start house-hunting, get pre-approved by a lender to confirm your actual rate and qualifying amount — this calculator gives you the knowledge to negotiate that process from a position of strength rather than guesswork.