Home Affordability Calculator - Income and DTI Estimate (2026)

Affordable price solves PITI = gross monthly × DTI − debts, then iterates PITI = P×[r(1+r)^n]/[(1+r)^n−1] + price×0.011/12 + 150 + HOA for P. On $120,000 income with $500 debts at 6.5% over 30 years and 43% DTI, max PITI is $3,800 and the solved price is about $395,000 with $50,000 down, giving $2,180 P&I.

Use 28% front-end (PITI/gross) and 36% back-end (PITI+debts/gross) as conservative guides, with 43% as the Qualified Mortgage maximum. On $10,000 monthly, 36% allows $3,600 for PITI+debts versus $4,300 at 43%, a $700 difference that changes max price by about $100,000 at 6.5%.

At $100,000 ($8,333 monthly) with $750 debts and $60,000 down, $400,000 at 6.5% 30-year with 1.1% tax and $150 insurance needs about $2,550 PITI, which is 30.6% front-end and 39.6% back-end. That exceeds 28% but is within 43%, so it is stretch affordable depending on other spending.

At 6.5% over 30 years, $500 less monthly for PITI reduces the loan by about $78,700 ( $500 / [r(1+r)^n/((1+r)^n−1)] ), which is about $98,000 less price with 20% down. Paying off a $500 auto loan before applying often beats saving another $10,000 down.

Twenty percent down avoids PMI on conventional loans. On $395,000 that is $79,000; 10% down is $39,500 and PMI at 0.7% adds about $124 monthly on the $355,500 loan. You can request PMI removal at 80% loan-to-value and it must be removed at 78% under the Homeowners Protection Act.

At $100,000 income with 28% PITI $2,333, raising the rate from 6.5% to 7.5% drops the affordable price from about $360,000 to about $320,000, losing $40,000. Dropping from 6.5% to 5.5% raises it to about $405,000, gaining $45,000, so locking a quote matters more than a small down payment change.

This calculator does not include: (1) closing costs of 2% to 5% of the loan ($6,880 to $17,200 on $344,000); (2) maintenance and utilities, typically $3,000 to $6,000 per year; or (3) future tax or insurance increases after closing. It assumes a fixed rate for the full term.

Lenders use gross monthly for DTI, so the 28%/43% math should use gross. For household budgeting, compare the PITI to take-home after taxes and retirement: $10,000 gross is about $7,800 take-home after 22%, so $2,800 PITI is 28% gross but 36% of take-home.

Tax rates vary from 0.3% in Hawaii to over 2% in New Jersey and Illinois. At 0.6% on $395,000, monthly tax is $198 versus $362 at 1.1%, freeing $164 monthly and raising affordable price by about $25,000 at 6.5%. Use your county rate for accuracy.

A 15-year payment is higher, so you afford less price at the same DTI. At $120,000 income, 43% PITI $3,800 at 6.5% 15-year supports about $285,000 versus $395,000 at 30-year, $110,000 less, but saves about $210,000 in interest and builds equity 2.6× faster in 5 years.