The Home Affordability Analyzer answers the single most important question before you begin house-hunting: How much home can you actually afford? It does this by applying the same underwriting ratios that lenders use — so the number you get is grounded in real qualification standards, not wishful thinking.

Affordability has two faces that often diverge sharply. The first is the mortgage amount a lender will approve. The second is the mortgage amount that leaves you financially healthy — able to save for retirement, handle emergencies, and maintain your lifestyle. This calculator addresses both, letting you compare your lender-maximum against your personal comfort ceiling.

According to the CFPB's homebuying guide, the median US home price in 2025 exceeds $400,000 in most major metro areas. At a 6.30% rate (Freddie Mac PMMS, April 2026), a buyer with $80,000 in household income and a $400 car payment can qualify for roughly $270,000 in mortgage under standard 28/36 rules — well below the median list price in cities like Seattle, Boston, Denver, or Miami.

The calculator accounts for all key affordability variables:

• Gross monthly income — the input lenders use (pre-tax, all verified sources)
• Front-end DTI (28% rule) — maximum PITI as a share of gross income
• Back-end DTI (36% rule) — maximum all-debt as a share of gross income
• Existing monthly debts — car loans, student loans, minimum credit card payments, child support
• Down payment — affects loan amount, PMI, and interest rate
• Estimated taxes, insurance, and PMI — which eat into your front-end headroom

Canadian readers: Canada uses Gross Debt Service (GDS ≤ 39%) and Total Debt Service (TDS ≤ 44%) ratios, set by CMHC. These are analogous to the US front-end and back-end ratios but allow slightly more housing cost as a fraction of income. All buyers must also pass the mortgage stress test (qualifying at contract rate + 2% or 5.25%, whichever is greater).

The 28/36 rule is the cornerstone of US mortgage affordability analysis, endorsed by Fannie Mae and incorporated into Freddie Mac's automated underwriting guidelines. It sets maximum ratios for two types of debt-to-income (DTI):

Working backward from DTI to maximum home price:

Example — $95,000 household income, $500/month existing debts, 6.30% rate, 30 years, 10% down:

Use the following walkthrough to produce a complete affordability picture. We'll use a dual-income household in a mid-tier metro as our example.

1. Gather your gross income figures.
   Lenders use pre-tax income from all verifiable sources. Base salary, overtime (averaged over 2 years), bonuses (averaged over 2 years), rental income (75% of gross), and documented investment income all count. Self-employment income uses the 2-year average from Schedule C after adding back depreciation and depletion. Our example: $120,000 combined gross income = $10,000/month.
2. List all monthly debt obligations.
   Include minimum credit card payments (not balance, just minimum), auto loans, student loan payments, personal loans, child support, and alimony. Exclude utilities, subscriptions, groceries, and current rent (rent is not counted as a debt in DTI calculations). Our example: $450 auto + $200 student loans = $650/month existing debt.
3. Calculate your down payment and available cash.
   Lenders want to see the down payment sourced and seasoned (typically 60 days in your account). Reserve requirements: most conventional loans want 2–6 months of PITI in reserves after closing. Our example: $60,000 available, with $50,000 for down payment and $10,000 remaining (about 3 months PITI reserve on a $3,000 payment — just adequate).
4. Estimate local property taxes and insurance.
   Use your target county's effective tax rate. National averages: 1.1% of purchase price for taxes, 0.4–0.8% for homeowners insurance. In high-cost states (NJ 2.47%, IL 2.27%, TX 1.80%), taxes alone can add $400–$700/month to PITI on a $400,000 home. Our example in Virginia (0.82%): $400,000 × 0.82% ÷ 12 = $273/month taxes; insurance $150/month.
5. Enter your data and apply the 28/36 rule.
   Front-end: $10,000 × 28% = $2,800 max PITI.
   Non-P&I monthly costs: $273 (tax) + $150 (insurance) + ~$120 (PMI at 0.58% on ~$250,000 loan) = $543.
   Max P&I: $2,800 − $543 = $2,257. At 6.30%, 30 years → max loan ~$377,000.
   Back-end: $10,000 × 36% = $3,600 − $650 debts = $2,950 max housing → max P&I $2,407 → max loan ~$402,000.
   Front-end is binding. Max loan: ~$377,000. With 12.5% down ($50,000 on a ~$427,000 purchase), total purchase price ≈ $427,000.
6. Compare lender max vs. personal comfort level.
   Some financial planners recommend targeting the 25% rule (25% of gross, not 28%) for a comfortable buffer. At 25%, the example buyer's comfortable max PITI = $2,500, max P&I = $1,957, max loan ≈ $327,000 — $50,000 below the lender maximum. Choosing the conservative figure preserves more cash for retirement savings, maintenance reserves, and lifestyle.
7. Stress-test against rate increases.
   If rates rise 1% (from 6.30% to 7.30%), the same $377,000 loan's payment rises from ~$2,338 to ~$2,576/month — a $238 increase that could push front-end DTI above 28%. The CFPB's rate explorer tool helps quantify this risk.

The analyzer produces four key outputs. Understanding each prevents overextension:

Maximum Purchase Price
This is the highest price at which you can both qualify for a mortgage and make the PITI payments within the 28/36 guidelines, given your income, debts, and down payment. This is a ceiling, not a recommendation. Experienced buyers typically purchase 10–15% below their lender maximum to maintain financial flexibility.

Front-End vs. Back-End Binding Constraint
Your affordability is determined by whichever ratio is more restrictive. If you have significant existing debt ($800+ per month), the back-end ratio typically becomes the binding constraint, limiting your home purchase independent of income. If you carry minimal debt, the front-end ratio (28%) generally limits you first. The analyzer shows you which constraint applies and by how much — revealing whether paying down existing debt or earning more income would have a larger impact on your buying power.

Income Needed for a Target Price
If you have a specific home in mind, the calculator inverts the equation: given a $500,000 purchase price with 10% down at 6.30%, 30 years, what gross annual income do you need? At 28% front-end: approximately $145,000/year in a low-tax market, or $165,000/year in a high-tax market like New Jersey.

PMI Tipping Point
The analyzer flags whether increasing your down payment to hit 20% (eliminating PMI) is financially optimal. On a $400,000 purchase: the difference between 10% ($40,000) and 20% ($80,000) down is $40,000 more upfront. PMI savings: approximately $167/month (0.58% on $360,000 remaining loan). Break-even: $40,000 ÷ $167/month ≈ 239 months (nearly 20 years). In most cases, buying with 10% down and investing the additional $40,000 in a diversified portfolio outperforms the PMI elimination strategy over a 5–10 year horizon.

Fannie Mae and FHA Maximum DTI Comparison
Fannie Mae's Desktop Underwriter system can approve DTIs up to 45–50% for borrowers with strong compensating factors (substantial reserves, high credit scores, low LTV). FHA allows up to 50% back-end DTI with compensating factors per HUD guidelines. However, borrowing at 45–50% DTI leaves very little margin for income disruption, emergency expenses, or lifestyle needs. The 28/36 rule is a guideline, not a guarantee of financial comfort.

Canadian GDS/TDS Comparison
Canadian lenders use GDS (housing costs ÷ income ≤ 39%) and TDS (all debts ÷ income ≤ 44%) as set by CMHC. GDS is more permissive than the US 28% rule, allowing more housing cost as a share of income, which partially explains why Canadian home prices remain elevated relative to US counterparts despite the stress test.

• Pay off installment debt before applying — the DTI impact is immediate.
  Eliminating a $350/month car payment increases your back-end DTI headroom by $350/month, which translates (at 6.30% / 30 years) to approximately $58,600 more in purchasing power. If you have $8,000 in savings above your emergency fund, paying off a car loan worth $350/month adds far more buying power than keeping the $8,000 as extra down payment.
• Add a co-borrower to increase qualifying income.
  A spouse, partner, or — in some states — a parent can be added as a co-borrower, stacking incomes for DTI calculation. A co-borrower earning $50,000/year adds $4,167/month to the income denominator, increasing maximum PITI by ~$1,167/month and maximum loan by approximately $195,000 at current rates. Both borrowers' credit scores and debts are included.
• Consider down payment assistance programs before assuming you need 20%.
  HUD-approved agencies administer state and local DPA programs that provide grants or forgivable second liens for first-time buyers, often income-limited to 80–120% of area median income (AMI). Many programs offer $10,000–$25,000 in assistance, effectively boosting buying power without increasing monthly debt.
• Get seller concessions on closing costs to preserve your down payment.
  Sellers can contribute up to 3–9% of the purchase price toward buyer closing costs depending on loan type and LTV (Fannie Mae guidelines). If you can negotiate $10,000 in seller concessions, you redirect that $10,000 toward a larger down payment, improving LTV, reducing PMI, and potentially improving your interest rate tier.
• Explore income-based repayment for student loans before applying.
  For FHA loans, student loan DTI is calculated at 1% of the outstanding balance per month OR the actual payment, whichever is greater. Switching to an IDR plan (Income-Driven Repayment) with a lower actual payment may reduce your DTI count if your lender uses actual payment. Fannie Mae now uses the actual IDR payment if it's greater than $0 per Fannie Mae guidelines updated 2023.
• Understand the difference between pre-qualification and pre-approval.
  Pre-qualification is a rough estimate based on self-reported data with no credit check. Pre-approval requires verified income, asset, and credit documentation, and results in a conditional commitment letter. In competitive markets, sellers routinely reject offers without pre-approval letters. A pre-approval also locks in underwriting review, so surprises at closing are far less likely.