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Home Affordability Calculator

Find the maximum home price you can afford from your income, debts, and down payment using the 28/36 rule.

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How to use

  1. 1.Enter your gross income and choose whether it is monthly or annual, then add your total recurring monthly debt payments (car loans, student loans, credit-card minimums).
  2. 2.Enter the cash down payment you plan to make, your expected annual interest rate, and the loan term in years.
  3. 3.Read the affordable home price, affordable loan amount, and maximum monthly housing payment — all recalculated instantly under the 28/36 rule.

About Home Affordability Calculator

The Home Affordability Calculator answers the question every buyer asks first: how much house can I actually afford? Instead of starting from a loan amount and working forward to a monthly payment (that is what a mortgage calculator does), this tool works in reverse. It starts from your income and existing debts, applies the industry-standard 28/36 debt-to-income (DTI) rule to find your maximum affordable monthly housing payment, then uses inverse loan amortization to translate that payment into a maximum loan amount — and finally adds your down payment to reveal the top home price in your realistic range.

Here is how the math works. The 28/36 rule sets two ceilings. The front-end ratio caps housing costs (principal and interest) at 28% of your gross monthly income. The back-end ratio caps all recurring debt — your future mortgage plus car loans, student loans, and minimum credit-card payments — at 36% of gross income. Your maximum housing budget is the smaller of these two numbers: min(0.28 × income, 0.36 × income − monthly debts). When your other debts are low, the 28% front-end ratio usually binds; when debts are high, the 36% back-end ratio pulls the number down, and if debts are very high the budget can drop to zero.

That monthly ceiling is then run through the annuity present-value formula (inverse amortization) at your interest rate and loan term to compute how large a loan that payment can support. Add your cash down payment and you get the affordable home price. Every calculation runs entirely in your browser — nothing you type is uploaded, saved, or shared.

Use it to sanity-check a listing before you tour it, to see how paying down a car loan or student loan raises your budget, to compare a 15-year versus 30-year term, or to understand how a bigger down payment expands your reach. Adjusting any input recalculates instantly, so you can explore trade-offs in seconds.

A few important caveats. The 28/36 rule is a widely used lender guideline, not a guarantee — real underwriting also weighs your credit score, cash reserves, employment history, and the specific loan program (FHA, VA, and conventional loans each use different limits, and some lenders stretch ratios higher). This estimate also covers only principal and interest; your true monthly cost will include property taxes, homeowners insurance, HOA dues, and possibly private mortgage insurance (PMI), which reduce the price you can comfortably carry. Treat the result as a starting benchmark for your search and budget conversations, then confirm the actual figures with a licensed mortgage professional before making an offer.

Methodology & sources

Uses the industry-standard 28/36 debt-to-income (DTI) rule to set the maximum monthly housing payment = min(0.28 × grossMonthlyIncome, 0.36 × grossMonthlyIncome − monthlyDebts), clamped to at least 0. That payment is converted to a maximum loan via inverse loan amortization (annuity present-value): with r = (annualRatePct/100)/12 and n = years × 12, loan = payment × ((1+r)^n − 1) / (r × (1+r)^n), or payment × n when r = 0. Affordable home price = loan + down payment. Assumptions: principal and interest only (no taxes, insurance, HOA, or PMI); fixed rate over the full term. The 28/36 rule is a widely used lender guideline, not a lending guarantee — actual approval depends on credit, reserves, and loan program. Estimates for general information only — not financial advice.

Frequently asked questions

What is the 28/36 rule?
It is a common debt-to-income guideline: spend no more than 28% of your gross monthly income on housing (front-end ratio) and no more than 36% on total debt including the mortgage (back-end ratio). Your maximum housing budget is the smaller of 28% of income and 36% of income minus your other monthly debts.
How is affordability different from a mortgage calculator?
A mortgage calculator starts with a loan amount and computes the monthly payment. This affordability calculator works in reverse: it starts with your income and debts, applies the 28/36 rule to find the largest payment you can carry, then uses inverse amortization to find the maximum loan and home price that payment supports.
Does this include property taxes, insurance, and PMI?
No. The estimate covers loan principal and interest only. Property taxes, homeowners insurance, HOA dues, and PMI add to your true monthly cost and would lower the home price you can comfortably afford. Add those separately, and confirm real limits with a licensed lender.

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