Data Sources &
Methodology
FinanceRateCalc is committed to transparency. Every number on this site comes from a verifiable source. Below is a complete breakdown of what we use, why, and how we calculate affordability.
Primary Data Sources
U.S. Bureau of Labor Statistics (BLS)
Occupational Employment and Wage Statistics (OEWS) — median annual wages by occupation and metropolitan area. Used for all profession-specific salary data (nurses, teachers, software engineers, etc.)
→ bls.gov/oes
U.S. Census Bureau — American Community Survey (ACS 2023)
Median household income by metro area, housing cost burden statistics, population demographics. Used for city-level income and demographic context.
→ census.gov/programs-surveys/acs
Zillow Home Value Index (ZHVI)
Median home values by ZIP code and metro area. Monthly updates. Used for all median home price figures.
→ zillow.com/research/data
Federal Reserve Economic Data (FRED)
30-year fixed mortgage rate averages, federal funds rate, economic indicators. Used for interest rate assumptions in all mortgage calculations.
→ fred.stlouisfed.org
HUD / FHA Official Guidelines
FHA loan limits, DTI thresholds, down payment requirements, MIP rates. Used for all FHA vs. conventional loan comparisons.
→ hud.gov
Fannie Mae / Freddie Mac Selling Guides
Conventional loan underwriting guidelines, DTI limits, LTV requirements. Used for conventional mortgage calculations.
→ fanniemae.com/research-and-insights
Walk Score
Walkability scores by neighborhood. Used as a lifestyle metric in city comparisons.
→ walkscore.com
How We Calculate Affordability
Monthly PITI Calculation
PITI = Principal + Interest + Taxes + Insurance. This is the standard lender calculation for total monthly housing cost.
Loan Amount = Home Price × (1 - Down Payment %)
Monthly Rate = Annual Rate ÷ 12
P&I = Loan × [r(1+r)³⁶⁰] ÷ [(1+r)³⁶⁰ - 1]
Property Tax = (Home Price × Annual Tax Rate) ÷ 12
Insurance = (Home Price × 0.5%) ÷ 12
PITI = P&I + Property Tax + Insurance
Debt-to-Income (DTI) Ratio
Front-End DTI = Monthly PITI ÷ Gross Monthly Income
Back-End DTI = (PITI + All Debt Payments) ÷ Gross Monthly Income
Conventional limit: 43-45% back-end
FHA limit: 50-57% with compensating factors
Default Assumptions
Interest Rate: 6.7% (30-year fixed, current market average)
Down Payment: 20% (unless otherwise specified)
Loan Term: 30 years
Insurance: 0.5% of home value annually
Property tax: City-specific rate from public records
Price-to-Income Ratio
Price-to-Income = Median Home Price ÷ Median Household Income
Historical healthy range: 3-5x
Current US average (2026): ~6.2x
What We Don't Do
We do not scrape, fabricate, or interpolate data without disclosure. All figures are either directly sourced from the agencies listed above or clearly labeled as estimates. When data is unavailable for a specific geography, we note it as an approximation.
Update Frequency
Mortgage rate assumptions are reviewed monthly. Home price data is updated quarterly using Zillow ZHVI. Salary data reflects the most recent BLS OEWS annual release. City-specific market trend data is updated as significant changes occur.
Important Disclaimer: All calculations are estimates for educational purposes only. Actual mortgage qualification depends on your specific credit score, debt load, lender overlays, and current market rates. FinanceRateCalc is not a lender and does not provide financial advice. Always consult a licensed mortgage professional for your specific situation.