Home Affordability Calculator

Enter your gross income, monthly debts, planned down payment and an interest rate to estimate the home price you can afford under the standard 28/36 lending guideline.

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Enter your details and press Estimate affordability.

The 28/36 affordability rule

A common lending guideline caps housing costs at 28% of gross monthly income (the "front-end" ratio) and total debt at 36% (the "back-end" ratio). The lower of the two limits determines how much can go toward a mortgage payment:

max P&I = min( 0.28·income , 0.36·income − debts ) − taxes & insurance

That maximum principal-and-interest payment is then converted into a loan amount with the standard mortgage formula, and the down payment is added back to get an affordable home price.

Worked example

$90,000/yr income ($7,500/mo), $400 other debt, $40,000 down, 6.5% over 30 yr, $350 tax+insurance:

28% rule: 0.28 × 7,500 = $2,100 for housing.
36% rule: 0.36 × 7,500 − 400 = $2,300 for total debt.
Available for P&I: $2,100 − $350 = $1,750/month.
Affordable home: ≈ $317,000 (loan ≈ $277k + $40k down).

What this estimate leaves out

This is a budgeting guide, not a pre-approval. It doesn't model PMI, HOA dues, closing costs, your credit score, or lender-specific overlays — all of which affect the real number. Treat the result as an upper bound and leave room for maintenance and emergencies.

Tip: a larger down payment lowers the loan and may remove PMI, while a lower rate sharply increases what you can afford. Check your DTI first with the DTI calculator.

Frequently asked questions

How much house can I afford?

A common rule caps housing at 28% of gross monthly income and total debt at 36%. On a $90,000 income with modest debts, that supports a home around $300,000–$320,000 depending on rate and down payment.

What is the 28/36 rule?

It limits housing costs to 28% of gross monthly income and all debt payments to 36%. The lower limit sets your maximum mortgage payment, which then determines the affordable loan and home price.

Does the down payment change what I can afford?

Yes. A bigger down payment doesn't change the payment-based loan limit, but it adds directly to the home price you can buy and may remove private mortgage insurance (PMI).

Is this a mortgage pre-approval?

No. It is an educational estimate using standard ratios. A lender's pre-approval also factors in your credit score, assets, PMI, taxes, insurance and program-specific rules.

MB
Mustafa Bilgic · Editor, Calcool
The 28/36 guideline reflects common U.S. underwriting practice. For home-buying basics see the Consumer Financial Protection Bureau (CFPB). This is an estimate, not a pre-approval, and excludes PMI, HOA and closing costs.

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