How this works
Updated
Independent editorial team. Every numeric claim cites a primary source — IRS / agency publication, federal or state statute, or controlling case law.
What the calculator computes
The calculator takes inputs you choose (role level, tenure, base salary, variable comp, state, age, filing status, termination type, equity, and medical premium) and computes: federal supplemental withholding (22% on the first $1,000,000 of supplemental wages in a calendar year, 37% above — IRC § 3402(g)), state supplemental withholding (from the state’s published rate table), FICA (Social Security 6.2% to the wage base, Medicare 1.45% on all wages, plus 0.9% above $200,000 single / $250,000 MFJ), federal WARN Act applicability (29 U.S.C. §§ 2101–2109) and any state mini-WARN, the OWBPA review window (21 days individual / 45 days group; 7-day revocation — 29 U.S.C. § 626(f)), COBRA premium cost from the monthly medical premium input, equity treatment at termination, and the Section 280G parachute-payment flag for executive packages.
Primary-source pipeline
Every numeric value is traced to a primary source. Federal rates come from IRS Publications 15 and 15-T, supplemented by IRC sections (Cornell LII). State supplemental withholding rates come from each state’s revenue department publication (CA EDD DE 44, NY Publication NYS-50, etc.). WARN thresholds come from the federal statute and state mini-WARN statutes (Cal. Lab. Code §§ 1400–1408 for California, N.Y. Lab. Law § 860 for New York, and the equivalent for each state). OWBPA timing comes from 29 U.S.C. § 626(f).
When sources differ, statutes control over regulations, regulations over agency publications, agency publications over news reporting. News reporting is cited only for publicly reported company practices, never for legal claims.
Calculator engine is unit-tested
The underlying engine (@calc/severance-engine in the source repository) is unit-tested against worked examples drawn directly from IRS publications and state revenue department publications. The test suite must pass on every change before deployment.
Corrections and changes
Material content changes are logged publicly on the Changelog page with the date of the fix. If you find an error, email hello@severancecalc.net with the page URL and the disputed claim.