Mortgage Affordability Calculator — All
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A mortgage affordability calculator estimates your maximum home price by combining income, monthly debts, down payment, interest rate, property taxes, homeowners insurance, and HOA dues. Most lenders start with the 28/36 rule: housing costs should stay near 28% of gross monthly income, and total debts should stay near 36%. FHA and some conventional loans can approve higher back-end DTI ratios, often 43% to 50%, when credit, reserves, or down payment are strong.

The 28/36 rule is the standard lender guideline: housing costs (mortgage principal + interest + taxes + insurance) should not exceed 28% of gross monthly income, and total debt payments (housing + car loans + student loans + credit cards) should not exceed 36%. Example: on a $100,000 gross annual income ($8,333/month), maximum housing is $2,333/month and total debt is $3,000/month. FHA loans allow higher ratios — up to 31% front-end and 43% back-end, with some lenders approving back-end DTI up to 57% with compensating factors like strong credit or large reserves.

Student loans count in your debt-to-income ratio regardless of deferment status. For conventional loans, lenders typically use 1% of the outstanding balance as the monthly payment if in deferment or income-driven repayment. For FHA loans (post-2021 guidelines), lenders use the actual payment amount on income-driven plans rather than 1%. If you have $80,000 in student loans on an income-driven plan with a $0 payment, FHA may count $0; a conventional lender would typically count $800/month. This difference alone can affect how much house you qualify for by $100,000+.

Minimum down payments by loan type: conventional loans (Fannie Mae/Freddie Mac) — 3% for first-time buyers, 5% for others; FHA loans — 3.5% with 580+ credit score, 10% with 500–579; VA loans — 0% for eligible veterans and active-duty service members; USDA loans — 0% for properties in eligible rural areas; jumbo loans (above conforming limits) — typically 10–20% depending on lender. A 20% down payment eliminates private mortgage insurance (PMI) on conventional loans, which saves $50–$200/month per $100,000 borrowed.

Private mortgage insurance (PMI) protects the lender if you default — it's required on conventional loans with less than 20% down. PMI typically costs 0.5%–1.5% of the loan amount annually, or $50–$150/month per $100,000 borrowed. On a $300,000 loan with 5% down, PMI might cost $125–$375/month. PMI is cancelable once your equity reaches 20% of the original purchase price — you can request cancellation, or it automatically terminates at 22% equity under federal law (Homeowners Protection Act of 1998). FHA loans have mortgage insurance premiums (MIP) that last the life of the loan if you put less than 10% down.

Self-employed borrowers — generally defined as owning 25%+ of a business — face additional scrutiny. Standard requirements: 2 years of personal and business tax returns, 2 years of business bank statements (for bank statement loans), a current profit-and-loss statement, and proof of 2+ years of self-employment. Lenders use the average of 2 years of Schedule C or K-1 income, not gross business revenue. Business write-offs that reduce taxable income also reduce qualifying income — a common trap. Bank statement loans (which use 12–24 months of deposits instead of tax returns) exist but typically require 10–20% down and carry higher rates.