Mortgage Affordability Calculator

The 28/36 rule is the foundation of mortgage qualification used by Fannie Mae and Freddie Mac, the two government-sponsored enterprises that back the majority of U.S. mortgages. The rule establishes two separate debt-to-income (DTI) ratio limits that borrowers must satisfy.

The Front-End Ratio (28%)

Your total monthly housing costs — including mortgage principal, interest, property taxes, homeowners insurance, and HOA fees (collectively called PITI) — should not exceed 28% of your gross monthly income. The Federal Housing Finance Agency (FHFA) uses this ratio as a primary qualification metric.

The Back-End Ratio (36%)

Your total monthly debt obligations (housing costs PLUS car payments, student loans, credit card minimums, and other recurring debts) should not exceed 36% of gross income. However, Fannie Mae's Desktop Underwriter system now accepts back-end DTI ratios up to 50% for borrowers with strong compensating factors such as high credit scores, substantial reserves, or large down payments.

* Assumes 7% rate, 30-year term, 20% down, 1.2% property tax, $1,200/year insurance.

The down payment is the single most controllable factor in home affordability. According to the National Association of Realtors' 2024 Profile of Home Buyers and Sellers, the median down payment for first-time buyers was just 8%, while repeat buyers averaged 19%.

The PMI Threshold: 20% Down

Putting less than 20% down triggers Private Mortgage Insurance (PMI), which protects the lender if you default. The Urban Institute's Housing Finance Policy Center reports that PMI typically costs 0.5–1.5% of the loan amount annually — adding $125–$375/month on a $300,000 loan. PMI can be removed once you reach 20% equity, per the Homeowners Protection Act of 1998.

Down Payment Comparison on a $350,000 Home

* At 7% interest, 30-year fixed. PMI estimated at 0.75% of loan annually.

First-Time Home Buyer Programs

The Federal Housing Administration (FHA) allows down payments as low as 3.5% with a 580+ credit score, making homeownership accessible with as little as $12,250 on a $350,000 home. Fannie Mae's HomeReady and Freddie Mac's Home Possible programs allow 3% down for borrowers earning ≤80% of area median income. Many state housing finance agencies (HFAs) offer additional down payment assistance grants of $5,000–$25,000 for qualified first-time buyers.

The loan type dramatically affects both qualification requirements and total cost of homeownership. The U.S. Department of Housing and Urban Development (HUD) reports that FHA loans accounted for 12.1% of all purchase mortgages in 2023, while VA loans represented 6.8%.

Conventional Loans

Backed by Fannie Mae or Freddie Mac, conventional loans require a minimum 620 FICO score and 3–20% down. PMI applies below 20% down but can be cancelled. The 2024 conforming loan limit is $766,550 in most areas ($1,149,825 in high-cost markets). Conventional loans offer the lowest rates for borrowers with 740+ credit scores, according to the ICE Mortgage Technology Origination Insight Report.

FHA Loans for First-Time Home Buyers

FHA loans are insured by the Federal Housing Administration and offer significantly more lenient qualification: 3.5% minimum down payment with 580+ credit score, or 10% down with 500-579 credit. The tradeoff is mandatory mortgage insurance premiums (MIP) — 1.75% upfront plus 0.55% annually — which cannot be cancelled for the life of the loan on most current FHA products.

VA Loans: Maximum Affordability for Veterans

VA loans, guaranteed by the Department of Veterans Affairs, offer the best affordability terms available: zero down payment required, no PMI, and competitive interest rates typically 0.25–0.50% below conventional rates. The VA's 2023 Annual Benefits Report shows the average VA purchase loan was $334,000 with a 2.67% funding fee. Eligible active-duty members, veterans, and surviving spouses can use this benefit with no maximum loan cap (after January 2020 Blue Water Navy Act changes).

* Most VA lenders require 580–620 as an overlay requirement.

One of the most searched mortgage questions — 'how much house can I afford on my salary?' — depends heavily on existing debt, down payment, local property taxes, and current interest rates. The Federal Reserve's Survey of Consumer Finances shows that the median American household carries $2,850/month in total debt obligations including housing.

I Make $45,000 a Year: How Much House Can I Afford?

At $45,000 annual gross income ($3,750/month), the 28% front-end ratio allows $1,050 for total housing. After property taxes (~$200/mo) and insurance (~$100/mo), about $750 remains for principal and interest. At 7% on a 30-year term with 5% down, this supports approximately $115,000–$130,000 in purchase price. FHA loans with 3.5% down could stretch this to $140,000, though MIP reduces the effective budget.

I Make $60,000 a Year: How Much House Can I Afford?

At $60,000 ($5,000/month), the 28% rule allows $1,400 for housing. After taxes and insurance, approximately $1,100 goes to P&I, supporting a purchase price of $175,000–$210,000 with 5% down at 7%. With 20% down and no PMI, buying power increases to approximately $230,000–$270,000.

I Make $100,000 a Year: How Much House Can I Afford?

At $100,000 ($8,333/month), $2,333 is available for housing at 28% DTI. After taxes and insurance, approximately $1,950 for P&I supports $310,000–$370,000 with 10% down. With 20% down and zero existing debt, this could reach $400,000–$450,000. The National Association of Realtors reports that households earning $100K+ purchased homes at a median price of $425,000 in 2023.

Mortgage affordability calculators that only show principal and interest give an incomplete picture. The Joint Center for Housing Studies at Harvard University identifies several recurring costs that add 30–50% on top of the base mortgage payment.

Property Taxes

The Tax Foundation reports the effective property tax rate ranges from 0.29% (Hawaii) to 2.23% (New Jersey). On a $400,000 home, that's a difference of $1,160 vs $8,920 per year — or $97 vs $743 per month. Always factor in your local rate, which you can find on your county assessor's website.

Homeowners Insurance

The Insurance Information Institute reports the average annual homeowners insurance premium is $2,230 nationally, with significant variation: $5,000+ in Florida and Louisiana vs $1,200–$1,500 in the Midwest. Homes in flood zones, wildfire areas, or hurricane corridors carry substantially higher premiums.

Maintenance and Repairs

The '1% rule' used by real estate professionals and endorsed by the American Society of Home Inspectors suggests budgeting 1% of home value annually for maintenance. On a $350,000 home, that's $3,500/year or $292/month. Older homes (pre-1980) should budget 1.5–2% due to aging systems, according to the National Association of Home Builders' component longevity data.

HOA Fees

The Community Associations Institute reports 74.2 million Americans live in HOA communities, with median monthly fees of $200–$400 for condos and $100–$250 for single-family HOAs. These fees directly reduce your borrowing power — a $300/month HOA fee reduces your affordable home price by roughly $45,000.