How We Verify Our Numbers
Our 5-step statutory verification process, primary government sources, and formula auditing changelog.
Our 5-Step Verification Process:
- Official Primary Sources Only: We extract data exclusively from primary statutory releases: IRS revenue procedures, CFPB regulations, and state departments of taxation.
- Standard Mathematical Formulas: All calculations utilize universally established formulas (such as standard annuity compound formulas and IRS Percentage Method withholding).
- Automated Unit Test Verification: Every calculator is tested against known benchmark cases using automated test suites before going live.
- Annual January Re-auditing: Every year, our research team audits changes in tax brackets, standard deductions, and retirement account contribution limits.
- Transparent Timestamps & Changelogs: Every tool visibly displays a "Last Updated" date so users can confirm formula recency.
Primary Official Sources
- Internal Revenue Service (IRS): Publication 15-T (Federal Income Tax Withholding), standard deduction tables, and tax bracket inflation adjustments.
- Consumer Financial Protection Bureau (CFPB): Home loan amortization rules, Truth in Lending Act (TILA) guidelines, and credit card minimum payment rules.
- Social Security Administration (SSA): Annual OASDI taxable maximum wage caps and benefit calculation factors.
- Federal Reserve: Benchmark interest rate tracking and consumer credit statistical releases.
Calculator Testing Examples
Here are two examples of benchmark test cases verified in our automated test suite:
| Calculator | Test Inputs | Expected Benchmark Result |
|---|---|---|
| Mortgage | $300,000 loan, 6.5% interest rate, 30-year fixed term | $1,896.20 / month (Principal & Interest) |
| Compound Interest | $10,000 principal, 7% annual return, 10 years annual compound | $19,671.51 final balance ($9,671.51 interest) |
| Credit Card Payoff | $5,000 balance, 20% APR, $200 monthly payment | 33 months payoff, $1,489.15 interest paid |
Changelog & Formula Updates
| Date | Tool Affected | Summary of Change |
|---|---|---|
| November 2026 | All Calculators | Updated 2026 standard deduction, FICA wage caps, and IRA/401(k) retirement limits. |
| October 2026 | Mortgage Calculator | Audited amortization formula and verified against CFPB loan disclosure guidelines. |
| September 2026 | Paycheck Calculator | Refactored federal withholding bracket calculations with unit test coverage. |
Report a Discrepancy
If you ever notice a calculation discrepancy or an outdated statutory parameter, please notify our research team immediately via our Contact Form. We investigate all formula reports within 24 business hours.