Mortgage Affordability Calculator
Our free mortgage affordability calculator helps you estimate how much house you can afford in seconds. Enter your income, monthly debts, down payment, and interest rate — no sign-up needed.
How to use this mortgage affordability calculator
Finding your price range takes under a minute. Simply follow these five steps and the calculator does the rest:
Enter your gross annual income — your salary before taxes and deductions.
Enter your total monthly debt payments — car loans, student loans, and credit card minimums.
Enter the down payment you plan to put toward the purchase.
Enter the annual interest rate your lender has quoted you.
Hit Calculate to see your max affordable home price and payment.
What is mortgage affordability?
Mortgage affordability is a measure of how much house you can comfortably buy without stretching your budget to the breaking point. Rather than guessing, lenders and financial planners use a time-tested guideline — the 28/36 rule — to draw that line.
The 28/36 rule explained
The 28/36 rule sets two guardrails. First, your total housing costs — mortgage principal and interest, property taxes, and homeowner's insurance — should not exceed 28% of your gross monthly income. Second, your total monthly debts, including that housing cost plus car loans, student loans, and credit card payments, should stay at or below 36% of your gross monthly income.
Our mortgage affordability calculator applies both limits and uses whichever is lower, so your estimate reflects the same standard most conventional lenders apply.
Front-end vs back-end ratio
The 28% figure is called the front-end ratio (housing only), while the 36% figure is the back-end ratio (all debts). If you carry significant monthly debts, the back-end ratio becomes the binding constraint — which is why paying down debt before house hunting can raise your affordable price.
Keep in mind that some loan programs allow higher ratios, but the 28/36 guideline remains the safest benchmark for comfortable, sustainable homeownership.
What affects how much house you can afford?
Four key factors determine what our mortgage affordability calculator shows as your price range. Understanding each one, therefore, helps you plan a stronger purchase.
Annual Income
Your gross income is the foundation of the calculation. A higher income raises both the 28% and 36% ceilings, directly increasing the home price you can support.
Existing Debts
Car loans, student loans, and credit card minimums eat into your 36% back-end limit. Reducing them is often the fastest way to qualify for a larger mortgage.
Down Payment
A bigger down payment is added straight onto your affordable loan amount. Reaching 20% also lets you avoid Private Mortgage Insurance (PMI), lowering your monthly cost.
Interest Rate
Lower rates mean the same monthly payment supports a larger loan. For instance, a 1% lower rate can add tens of thousands to your affordable price on a 30-year loan.
Mortgage affordability formula
Our mortgage affordability calculator applies the standard 28/36 rule that lenders use, then converts your affordable monthly payment into a home price with the fixed-rate mortgage formula:
Your affordable payment is the lower of those two numbers. That payment is then converted into a loan amount:
Finally, your down payment is added to the loan amount to give the max home price. You do not need to apply any of this yourself — the calculator above handles all the math instantly when you hit Calculate.
Example affordability calculation
To illustrate how the calculator works, here is a real-world scenario. Suppose you earn $100,000 per year, pay $500 per month in debts, have a $20,000 down payment, and qualify for a 6.5% rate on a 30-year loan:
What this example tells us
As this scenario shows, the 28% front-end rule is the binding constraint here — the 36% rule would allow up to $2,500 per month for housing, but the 28% cap of $2,333 keeps the estimate conservative. Notice also how the down payment is added directly on top: every extra $10,000 saved raises your affordable price by exactly $10,000.
Tips to improve your home affordability
If your mortgage affordability calculator result feels too low, several practical strategies can raise it. Consider these options before you start house hunting:
Pay down existing debts
- Target high-interest balances first — clearing a $300 monthly car payment can lift your affordable price by nearly $50,000 on a 30-year loan at typical rates.
- Avoid new debt before applying — opening new credit lines or financing furniture right before a mortgage application shrinks your back-end room.
Grow your down payment
- Save toward 20% — crossing the 20% threshold eliminates Private Mortgage Insurance (PMI), which effectively stretches every dollar of your monthly budget further.
- Every dollar counts directly — unlike rate shopping, each extra dollar saved for a down payment adds exactly one dollar to your affordable home price.
Strengthen your credit profile
- Improve your credit score — a higher score typically qualifies you for a lower interest rate, which directly increases the loan your payment can support.
- Shop at least three lenders — additionally, comparing quotes often uncovers rate differences of 0.25% to 0.5%, worth tens of thousands in buying power.
Learn more from trusted sources
Further reading from trusted US government resources:
Consumer Financial Protection Bureau — Owning a Home HUD.gov — Buying a Home GuideRelated tools on WebTools
Once you know your affordable price range, these tools can help with the next steps:
Mortgage Payment Calculator — Estimate your monthly payment for any loan Closing Costs Estimator — Find out how much you will pay at closing Profit Margin Calculator — Plan your finances before buying