House Affordability Calculator
Estimate affordable home price from income, debts, down payment, and rate.
A house affordability calculator estimates the maximum home price you can reasonably afford based on your gross income, existing monthly debts, down payment savings, and current mortgage rates. Lenders use a debt-to-income (DTI) ratio to determine how much they'll approve you to borrow, and this calculator applies the same underlying logic to give you a realistic price range before you start house hunting.
Enter your gross annual income, monthly debt payments, available down payment, and an estimated interest rate to see an estimated maximum affordable home price and monthly payment.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| $7,000/month gross income, 36% DTI limit, $300/month existing debt | $2,220/month max housing payment | Max total debt payment = $7,000 × 0.36 = $2,520. Subtract existing debt: $2,520 − $300 = $2,220 available for a mortgage payment. |
| $5,000/month gross income, 43% DTI limit, $700/month existing debt | $1,450/month max housing payment | Max total debt payment = $5,000 × 0.43 = $2,150. Subtract existing debt: $2,150 − $700 = $1,450 available for a mortgage payment. |
How Lenders Calculate What You Can Borrow
Mortgage lenders generally use two debt-to-income thresholds: a front-end ratio (housing costs alone, typically capped around 28% of gross monthly income) and a back-end ratio (all debts including housing, typically capped around 36-43% depending on the loan program). Conventional loans often allow back-end ratios up to around 43-45% for well-qualified borrowers, while some government-backed programs allow higher ratios in certain circumstances. This calculator applies similar thresholds to estimate your affordable range, though your specific approved amount will depend on your lender's exact guidelines and your full financial profile.
Why Affordable and Approved Are Not the Same Thing
A lender might approve you for a larger mortgage than you're personally comfortable paying every month - approval is based on debt ratios, but it doesn't account for your other financial goals like retirement savings, an emergency fund, or discretionary spending. Many financial planners suggest treating the lender's maximum approval as a ceiling, not a target, and choosing a home price that leaves comfortable room in your monthly budget beyond just the mortgage payment.
How Down Payment Size Changes Affordability
A larger down payment increases your affordable home price two ways: it directly reduces the loan amount needed for a given price, and if it reaches 20% of the home price, it eliminates the added cost of private mortgage insurance (PMI), which otherwise adds to your monthly housing cost and reduces your affordable price at a given debt-to-income ratio.
How to Use the House Affordability Calculator
- Open the House Affordability Calculator and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the house affordability calculator works.
Frequently Asked Questions
How expensive of a house can I afford based on my salary?
A common guideline caps total monthly debt payments (including the new mortgage) at around 36-43% of gross monthly income, though the exact ratio your lender allows depends on the loan program and your overall financial profile.
What is a debt-to-income ratio and why does it matter for buying a home?
Debt-to-income (DTI) ratio is your total monthly debt payments divided by your gross monthly income. Lenders use it to determine how much additional mortgage debt you can reasonably take on - lower existing debt generally means a higher affordable home price.
Does a bigger down payment increase how much house I can afford?
Yes, in two ways: it directly reduces the amount you need to borrow, and reaching 20% down eliminates PMI, which frees up more of your monthly budget for the mortgage payment itself.
Should I borrow the maximum amount a lender approves me for?
Not necessarily. Lender approval is based on debt ratios alone and does not account for your other financial goals - many financial planners recommend leaving comfortable room in your budget below the maximum approved amount.
What is the difference between front-end and back-end DTI ratios?
Front-end DTI counts only housing costs against your income (often capped around 28%), while back-end DTI counts all debts including housing (often capped around 36-43%). Lenders typically check both.
Does this calculator guarantee mortgage approval?
No. This is an estimate based on common lending guidelines, not a pre-approval. Getting pre-qualified with an actual lender is necessary to know your real approved amount, which depends on your credit score and full financial picture.
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Last updated: September 27, 2026.