Home Affordability: 28/36 Rule Max Price

What Is a Home Affordability Calculator and Why You Need One?

Bank says you can afford $600k. But can you really? The 28/36 rule is what most lenders still use as a budgeting reference — 28% of gross income for housing, 36% for all recurring debts. This affordability calculator flips the mortgage math — you give it income, debts, down payment, and it tells you price you can handle, not just what a listing site says.

Many buyers start with a mortgage payment. This calculator starts with your budget. Enter gross monthly income, car and student loan minimums, and target down payment. It estimates max housing payment that keeps you within 28% front-end and 36% back-end guidelines, then works backward to loan amount and home price using standard mortgage amortization. It is an educational budgeting estimate, not a loan approval.

The 28/36 Rule In Plain English

Make $8,000 per month gross. 28% = $2,240 for PITI+HOA+PMI. If taxes are $400, insurance $150, HOA $200, PMI $200, that leaves about $1,290 for principal and interest. At 6.75% 30-year, that supports about $197,000 loan. Add your $50,000 down, price about $247,000. That feels low compared to online ads, but that is the math when you include taxes and other costs.

Back-end matters too. 36% of $8,000 = $2,880 total debts. If you have $500 car + $300 student loans = $800 debts, housing must be $2,080 max to stay within 36%. So $2,080 is your cap, not $2,240. The lower of the two caps controls affordability. This calculator uses strict min(28%, 36% minus debts) to keep both ratios in check.

How To Use This Affordability Calculator

Enter $100,000 annual income ($8,333 per month), $800 monthly debts, $50,000 down, 6.75% rate, 30-year term, $6,000 annual taxes, $1,800 insurance, 0.75% PMI rate if down less than 20%, and $0 HOA. Calculator shows max housing about $2,333 at 28% and $2,200 at 36% minus debts ($3,000 minus $800). Allowed PITI+PMI+HOA is $2,200. After $650 taxes, insurance and HOA, about $1,550 remains for P&I plus PMI. That supports about $237,000 loan, price about $287,000. Adjust down payment or debts to see price change.

What Counts as Housing Payment for 28%?

Lenders do not count just principal and interest. For 28% rule, they count PITI plus HOA and PMI. That is Principal + Interest + property Taxes + homeowners Insurance + HOA dues + Private Mortgage Insurance if you put less than 20% down. Many first-time buyers forget taxes and HOA, then wonder why payment is $500 higher than a simple mortgage calculator showed. Taxes alone can be $400 to $1,200 per month depending on location. Always add taxes and insurance from county records and insurance quotes, not estimates.

Front-End vs Back-End DTI - Why Both Matter

Front-end DTI is housing divided by gross income — target 28% for budgeting. Back-end DTI is housing plus all recurring debts divided by gross income — target 36%, some lenders allow up to 41% to 45% with strong credit and reserves. Recurring debts are car loan, student loan, minimum credit card payments, child support, personal loan. They do not count groceries, utilities, or subscriptions. If your back-end is over 45%, even with good credit, many loan programs will ask you to pay down debts first or increase down payment.

How Down Payment and Rate Change Your Affordable Price

Down payment helps two ways. More down means smaller loan and potentially no PMI. Example: $300,000 price with 5% down at 6.75% means $285,000 loan plus about $180 monthly PMI. With 20% down, loan $240,000 and no PMI — payment drops by about $450 to $500. Rate matters even more. Same $240,000 loan is about $1,556 at 6.75% and $1,011 at 3.5%. That is why affordability feels low in higher rate periods. You cannot control rates, but you can control debts, down payment savings, and credit score which influences your rate tier. Aim to buy when back-end DTI is under 36% and you have 3 to 6 months reserves after closing.

How This Calculator Estimates Max Price

Step 1: Convert annual income to monthly. If you enter monthly income, that value is used. Otherwise annual divided by 12.

Step 2: Calculate 28% housing cap = monthly income × 0.28 and 36% total debt cap = monthly income × 0.36.

Step 3: Allowed housing = min(28% cap, 36% cap minus monthly debts). If debts push 36% cap below 0, allowed housing is 0.

Step 4: Subtract monthly taxes, insurance, HOA to get available P&I plus PMI budget. If down less than 20% and PMI rate greater than 0, affordable loan = (allowed housing minus escrow) divided by (mortgage factor + PMI factor). Otherwise affordable loan = (allowed housing minus escrow) divided by mortgage factor. Mortgage factor = r(1+r)^n / ((1+r)^n−1).

Step 5: Max price = affordable loan + down payment. Cash to close estimated as down plus 2.9% of price for closing fees.

Real Example - $100k Income, $800 Debts

Income $100,000 annual = $8,333 per month. 28% = $2,333. 36% = $3,000. 36% minus $800 debts = $2,200. Allowed housing = min($2,333, $2,200) = $2,200. Taxes $6,000 annual = $500 per month, insurance $1,800 = $150, HOA $0, escrow $650. Available for P&I plus PMI = $1,550. At 6.75% 30-year, factor about 0.00653. Without PMI, loan about $237,000, price about $287,000. With PMI at 0.75% if down 15%, loan lower. This example shows why back-end often controls.

Tips To Increase Affordable Price Without Stretching

• Pay down monthly debts before buying — every $100 debt reduction adds about $100 to allowed housing under 36% rule and about $15,000 to loan at 6.75% 30-year.
• Save larger down payment — reduces loan and may remove PMI.
• Improve credit to lower rate — even 0.5% lower rate adds about $15,000 to $20,000 buying power on same payment.
• Choose lower tax or HOA area — $200 less monthly tax/HOA adds about $30,000 to affordable loan.
• Keep reserves — 3 to 6 months after closing — not just down payment.

Important Limitations

This tool gives you a quick math-based estimate so you can budget smarter. It is not a loan approval, not a rate lock, and not your final Closing Disclosure. Taxes, insurance, county fees, HOA, PMI and lender pricing change. For exact numbers, always check with your lender or servicer. Conforming loan limits vary by county. This calculator uses 2.9% closing-cost assumption for cash-to-close estimate. Actual closing costs vary by lender, location and loan program.

Frequently Asked Questions

What is 28/36 rule?

28% of gross income for housing, 36% for housing plus recurring debts. Traditional budgeting guideline, not a universal approval rule. Many lenders allow higher with strong credit and reserves, but 28/36 is conservative for budgeting.

Does affordability include property tax and HOA?

Yes. Affordability should include principal, interest, property taxes, homeowners insurance, HOA and PMI when down payment is less than 20%. Not just P&I.

Why is my affordable price low now compared to 2021?

High rates cut buying power. At 3% a $1,600 P&I supports about $379,000 loan. At 6.75% same $1,600 supports about $246,000 loan. That is $133,000 less price for same payment.

What counts as monthly debts for 36%?

Car loan, student loan, minimum credit card payments, personal loan, child support. Not groceries, utilities, phone, subscriptions. Only recurring minimums reported on credit.

Does this calculator determine mortgage approval?

No. It provides educational budgeting estimates based on inputs you provide and 28/36 guideline. It does not determine eligibility, approval, rate quote or guarantee. Lenders use their own underwriting.