Data Sources
Every number, rate benchmark, and threshold on PayoffCalcs comes from a primary US government
source. No third-party aggregators, no scraped data, no unsourced claims. Below is the complete
list of agencies and datasets we reference, what we use each for, and when we last updated.
Interest Rates & Benchmarks
| Source | Dataset | What we use it for |
|---|
| Freddie Mac | Primary Mortgage Market Survey (PMMS) | Weekly average 30-year and 15-year fixed mortgage rates — used as rate context in the mortgage and refinance calculations |
| Federal Reserve | H.15 Selected Interest Rates | Benchmark interest rates, Treasury yields, and federal funds rate context |
| Federal Reserve | G.19 Consumer Credit | Average credit card APRs (by card type), auto loan rates, personal loan rates, and revolving credit trends |
Consumer Finance & Lending Rules
| Source | Resource | What we use it for |
|---|
| CFPB | Ask CFPB & Consumer Resources | Amortization guidance, DTI definitions, debt payoff rules, mortgage prepayment explanations, credit card agreement database |
| Fannie Mae | Selling Guide / Eligibility Matrix | DTI thresholds, income calculation standards, conventional loan requirements, and underwriting guidelines |
| HUD / FHA | FHA Mortgage Limits & Guidelines | FHA DTI limits (front-end/back-end), housing affordability standards, and first-time buyer program parameters |
Taxes & Deductions
| Source | Publication | What we use it for |
|---|
| IRS | Publication 936 — Home Mortgage Interest Deduction | Mortgage interest deductibility rules, limits, and qualifying criteria used in after-tax mortgage cost context |
| IRS | Revenue Procedure (annual) | Federal income tax brackets, standard deduction amounts, and contribution limits for retirement accounts |
Demographics & Benchmarks
| Source | Dataset | What we use it for |
|---|
| Federal Reserve | Survey of Consumer Finances (SCF) — triennial | Net worth benchmarks by age, debt distribution, income percentiles, savings rate data, and wealth inequality context |
| US Census | American Community Survey (ACS) | Income distribution by metro area, housing costs, rent vs buy benchmarks, and demographic context for affordability |
| Bureau of Labor Statistics | Consumer Expenditure Survey | Average household spending by category — used for budget context and expense benchmarks |
Investing & Retirement
| Source | Resource | What we use it for |
|---|
| SEC | Investor.gov Education Resources | Compound interest education, investment return context, investor protection framework |
| Social Security Administration | Cost-of-Living Adjustments & Benefit Data | Retirement income context, COLA adjustments, and benefit benchmarks for retirement planning |
Data Freshness
| Data type | Update frequency | Last updated |
|---|
| Tax brackets & deductions | Annually (when IRS releases) | 2026 tax year |
| DTI thresholds & lending rules | As rules change (monitored) | August 2026 |
| Credit card APR benchmarks | Quarterly (Fed G.19) | Q1 2026 |
| Mortgage rate context | Quarterly (Freddie Mac PMMS) | August 2026 |
| Net worth & income percentiles | Every 3 years (Fed SCF) | 2022 SCF (next: 2025) |
When a source updates, we refresh the relevant calculators within 30 days. Questions about a
specific number? Email us.