Mortgage Affordability Calculator
Find out how much house you can afford based on your income, debts, and down payment.
Your estimated monthly mortgage payment is $1,896 for a $300,000 loan at 6.5% over 30 years.
Why This Calculation Matters
The Mortgage Affordability Calculator helps you make better mortgages decisions by putting the math directly in front of you. Instead of relying on averages or guesswork, plug in your own numbers and see how the key inputs, rate, term, amount, and timing, interact. Small changes to any one of them can have outsized effects over years or decades.
How to Use This Calculator
- Enter your values in the input fields, each one has a label and help text explaining what to type.
- Results appear instantly as you type; there's no "calculate" button to press.
- Change any input to compare scenarios side by side.
All math happens in your browser. Nothing you type is sent to a server, saved, or shared.
Key Inputs to Get Right
The most important numbers are usually the interest rate and the time horizon. Over years or decades, small rate differences compound into large dollar differences, so it's worth sanity-checking the rate against current market data before acting on any result.
How Much House Can You Afford?
Lenders typically use the 28/36 rule: your mortgage payment shouldn't exceed 28% of gross monthly income, and total debts shouldn't exceed 36%.
Factors That Affect Affordability
- Income: Higher income means higher affordable payment
- Debts: Existing debts reduce borrowing capacity
- Down payment: Larger down payments mean smaller loans
- Interest rate: Lower rates increase purchasing power
- Property taxes: Vary significantly by location
When to Use This Calculator
- Model scenarios before making a major financial decision involving mortgages.
- Compare different inputs side by side to see how rate, term, or amount changes your outcome.
- Sanity-check numbers a lender, advisor, or spreadsheet has given you.
- Build a realistic financial plan grounded in your actual numbers, not averages.
Limitations & Common Mistakes
- Results are estimates, actual terms depend on credit, lender policy, taxes, and fees not captured here.
- Rates and prices change daily; recompute with current numbers before signing documents.
- Does not constitute financial advice. For major decisions, consult a licensed advisor.
Frequently Asked Questions
What is the 28/36 rule?
The 28/36 rule is a lending guideline where your monthly housing costs should not exceed 28% of your gross monthly income, and your total monthly debt payments should not exceed 36% of your gross monthly income.
How much should I put down on a house?
Ideally 20% to avoid PMI (private mortgage insurance). However, FHA loans allow as little as 3.5% down and conventional loans may accept 3-5% down. A larger down payment means lower monthly payments and less interest paid overall.
How accurate is the Mortgage Affordability Calculator?
Results use standard financial formulas and are a reliable planning estimate. Exact numbers depend on your lender's rates, fees, and underwriting, always verify with a loan estimate before signing.
Does this account for taxes, insurance, and fees?
The calculator shows the core figure by default. Taxes, insurance, PMI, HOA dues, and closing costs can materially change your monthly cost, factor them in when budgeting.
Is this calculator free to use?
Yes. The Mortgage Affordability Calculator is free, requires no signup, and runs entirely in your browser, your inputs are never sent to a server.
Related Calculators
More Finance →Mortgage Payment Calculator
Calculate your monthly mortgage payment including principal and interest. See total cost over the life of your loan.
Down Payment Calculator
Calculate how much you need for a down payment and how it affects your monthly mortgage payment.
Income Tax Calculator
Estimate your federal income tax based on filing status, income, and deductions.
Key terms
- Debt-to-Income Ratio (DTI)The percentage of your gross monthly income that goes to minimum debt payments. Mortgage underwriters use DTI as the primary affordability gate: most convention…
- Private Mortgage Insurance (PMI)Insurance required by most lenders when a conventional mortgage borrower puts less than 20% down. PMI protects the lender, not the borrower, against default los…
Related guides
- Reading Your Paycheck: What Every Deduction Actually Means in 2026Federal income tax, FICA, Medicare surtax, state tax, 401(k), HSA, FSA, health premiums, garnishments, line by line, with the exact 2026 rates and thresholds applied to real sample paychecks.
- Compound Interest, Explained in the Math Your Calculator Actually UsesThe formula A = P(1 + r/n)^(nt) is one of the most useful equations in personal finance. Here is how each variable actually behaves, and why compounding frequency matters less than you think.
- Why the 28/36 Rule Fails Most Homebuyers in 2025The classic mortgage-affordability rule was built for a world without student loans, rising property taxes, or $8,000 HOA dues. Here is a better framework, and the DTI math lenders actually use.