House Affordability Calculator
ToolYard's House Affordability Calculator shows how much home you can reasonably buy based on your income, debts, and local costs. Enter your interest rate, loan term, down payment, property tax, insurance, and HOA dues to see a full PITI estimate. Choose By Income to find the maximum affordable price, By Price to learn the income required for a specific home, or Reverse to work backward from a target monthly payment. The tool also accounts for PMI when your down payment is below 20%, estimates when PMI drops off, and includes a quick rate stress test so you can compare affordability at higher interest rates. Everything runs in your browser for privacy.
What Is a Home Affordability Calculator?
A home affordability calculator estimates the maximum home purchase price you can qualify for based on your income, existing debts, down payment, interest rate, and the lender's debt-to-income (DTI) limits. It translates your financial profile into a concrete price ceiling — the same way a mortgage underwriter does.
The calculation uses PITI — Principal, Interest, Taxes, and Insurance — as the full monthly housing cost. Lenders apply two DTI rules: the front-end ratio (housing costs ÷ gross income) and the back-end ratio (all debts ÷ gross income). Whichever limit is stricter sets your ceiling.
ToolYard's calculator applies both DTI rules simultaneously, so the result reflects the actual lender test — not just a 3× income shortcut. Enter your numbers to see your max price, estimated monthly PITI, and required down payment.
How to Use This Home Affordability Calculator
- Enter your gross annual income (before taxes). Include all household earners.
- Enter your monthly debt payments: car loans, student loans, credit card minimums — anything that appears on a credit report.
- Enter your down payment amount or percentage.
- Set the interest rate (use current 30-year fixed rates or your pre-approval rate).
- Adjust property tax rate, homeowners insurance, and HOA if known.
- The calculator outputs your max home price, estimated PITI, and DTI breakdown.
Worked Example: The Chen Family
The Chens earn a combined $120,000/year ($10,000/month gross) with $800/month in existing debts (car payment + credit card minimums). They have $55,000 saved for a down payment. Current 30-year fixed rate: 7.0%.
- Front-end limit (28%): max PITI = $2,800/month
- Back-end limit (36%): max total debt = $3,600 → max PITI = $3,600 − $800 = $2,800/month (same)
- After deducting $500/month for taxes + insurance: max P&I = $2,300/month
- At 7% for 30 years, $2,300/month supports a loan of ~$345,000
- Loan + down payment: $345,000 + $55,000 = $400,000 max purchase price
The Chens should shop in the $350,000–$400,000 range and keep a $20,000 buffer for closing costs and reserves.
Home Affordability by Income — Reference Table
| Annual Income | Monthly Gross | Max PITI (28%) | Max Price (10% down, 7%) |
|---|---|---|---|
| $60,000 | $5,000 | $1,400 | ~$185,000 |
| $80,000 | $6,667 | $1,867 | ~$255,000 |
| $100,000 | $8,333 | $2,333 | ~$325,000 |
| $120,000 | $10,000 | $2,800 | ~$400,000 |
| $150,000 | $12,500 | $3,500 | ~$510,000 |
| $200,000 | $16,667 | $4,667 | ~$690,000 |
Assumes no existing debts, 10% down, 7% rate, $500/month taxes + insurance. Actual results vary by market and credit.
Key Concepts: PITI, DTI, PMI, and Front/Back-End Ratios
PITI — Principal + Interest + Taxes + Insurance. This is the full monthly housing obligation lenders evaluate, not just the P&I mortgage payment. Forgetting taxes and insurance inflates affordability estimates by 15–25%.
Front-end DTI — PITI ÷ gross monthly income. Conventional limit: 28%. FHA: 31%. VA: no official limit but prefers under 41%.
Back-end DTI — (PITI + all other debts) ÷ gross monthly income. Conventional: 36–43%. FHA: 43–50% with compensating factors. This ratio is often the binding constraint for buyers with car payments or student loans.
PMI (Private Mortgage Insurance) — Required when down payment is under 20% on conventional loans. Costs 0.5–1.5% of the loan balance per year ($83–$250/month on a $200,000 loan). PMI cancels automatically when equity reaches 22%, or you can request removal at 20%.
Tips and Common Mistakes
- Using take-home pay instead of gross income — Lenders use gross (pre-tax) income for DTI. Using net income understates your buying power by 20–35%.
- Forgetting closing costs — Budget 2–5% of purchase price ($8,000–$20,000 on a $400,000 home) on top of your down payment. These cannot be rolled into most conventional loans.
- Maxing out your budget — Qualifying for a price doesn't mean it's wise to spend it. A 10–15% cushion below max protects against rate increases if you use an ARM, job changes, or unexpected repairs.
- Not accounting for HOA — HOA fees are included in PITI by lenders. A $400/month HOA on a condo reduces your max loan by ~$55,000 at 7%.
- Ignoring property tax variations — Effective rates range from 0.3% (Hawaii) to 2.5% (New Jersey). On a $400,000 home, that's $100–$833/month — a difference that dramatically shifts max affordability.
Frequently Asked Questions
How much house can I afford on a $80,000 salary?
Roughly $230,000–$270,000 with 10% down and no significant existing debts at a 7% rate, using the 28% front-end DTI rule. The calculator will give you an exact figure based on your specific debts, rate, and taxes.
What DTI ratio do lenders use?
Conventional loans typically require front-end DTI ≤28% and back-end DTI ≤36–43%. FHA loans allow 31%/43%, and some lenders allow up to 50% back-end with strong compensating factors (large down payment, high credit score).
Does the calculator account for PMI?
Yes. When down payment is below 20%, PMI is estimated at 0.85% of the loan annually and added to PITI, which reduces the maximum loan amount the DTI calculation allows.
What income counts for a mortgage?
W-2 wages, salary, self-employment income (2-year average), rental income (75%), Social Security, pension, and investment distributions. Part-time income counts if it has a 2-year history. Bonuses count if documented for 2+ years.
How does interest rate affect affordability?
A 1% rate increase reduces buying power by roughly 10%. At 6%, a $2,000/month P&I supports a $333,000 loan; at 7% it supports $300,000 — a $33,000 drop. Always run the calculator with current rates, not historical averages.
What is a good front-end DTI for a mortgage?
Under 28% is conventionally ideal. 28–31% is acceptable for FHA. Above 31% requires compensating factors. Lenders look more favorably at 25% or below, which leaves budget room for ownership costs beyond the mortgage.
How much should I save before buying a home?
Down payment (3–20%) + closing costs (2–5%) + 3–6 months PITI as emergency reserve. On a $350,000 home with 10% down: $35,000 + $10,500 + $12,000 = ~$57,500 minimum before shopping.
What related tools should I use?
Use the mortgage calculator to see your exact payment, the down payment calculator to compare scenarios, or the rent vs buy calculator to decide whether buying makes sense yet.