How we calculate the numbers.

Data sources

The model is built on public datasets and published industry surveys. The primary sources:

• Tax Foundation — state individual income tax rates and brackets.
• U.S. Department of Labor, Employment & Training Administration (DOL ETA) — weekly unemployment insurance maximums and maximum benefit durations by state.
• National Conference of State Legislatures (NCSL) — mini-WARN provisions: employee thresholds, notice periods, statutory severance triggers.
• State DOLs — authoritative source of last resort for severance/UI interaction rules and state-specific notice law.
• Bureau of Labor Statistics (BLS) — layoff studies and re-employment duration baselines.
• Lee Hecht Harrison, Mercer, and RiseSmart — published industry severance benchmarks used to anchor the per-year weeks figure for each sector.

The severance formula

The midpoint estimate for a given offer is calculated as:

weeksPerYear × yearsOfService × companySizeMultiplier × weeklyPay

The weeksPerYear term is the industry baseline drawn from the benchmark surveys above — tech, finance, and pharma anchor higher; retail, hospitality, and logistics anchor lower. The companySizeMultiplier adjusts that baseline up or down because publicly reported packages at larger employers tend to be more generous than those at small businesses. A floor at the industry-specific minWeeks value keeps employees with very short tenure from collapsing toward zero. Because situations vary, the result is presented as a range with low and high bounds, not a single point.

Tax math

Severance is supplemental wages for federal withholding purposes. The model applies a flat 22% federal supplemental rate (the 37% rate above $1M in a calendar year is also handled for high earners). FICA is applied as 6.2% Social Security up to the annual wage base, plus 1.45% Medicare on all wages and an additional 0.9% Medicare surtax on wages above $200,000 in a year. State withholding uses the top marginal income tax rate for the selected state, which is conservative for most filers and correct for high earners; it intentionally does not try to model brackets, deductions, or credits, because the calculator does not collect enough information to do so honestly.

WARN check

The model first applies the federal floor: employers with 100 or more full-time employees must provide 60 calendar days of written notice before a covered mass layoff or plant closing. It then layers any stricter state mini-WARN rule on top — a lower employee threshold, a longer notice window, or in a few states (notably New Jersey) statutory severance. Whichever is more protective of the worker controls. The check is a flag, not a legal opinion: if it lights up, the next step is talking to an employment attorney in your state.

Runway

Runway is the months of monthly expenses that the package can cover. It is calculated as net severance (after federal, FICA, and state withholding) plus total unemployment insurance benefits over the period you are eligible, divided by your stated monthly expenses. The UI calculation honors state-specific severance/UI interaction rules: some states pay UI concurrently with severance, some delay UI until the severance period ends, and some reduce the weekly UI benefit in proportion to severance received. The state data file captures which rule applies in each jurisdiction.

Verdict

The fairness verdict compares the actual offer you entered to the low and high bounds of the calculated range: below the low bound is flagged as below-market; between the low and high bounds is flagged as within the fair range; above the high bound is flagged as above-market. The verdict is descriptive, not prescriptive — an offer below the range is not automatically wrong (your tenure or industry may justify it) and an offer above the range is not automatically generous (your circumstances may warrant more).

Refresh cadence

The state data file is reviewed monthly via an internal refresh skill that pulls the latest tax rates, UI maxes, durations, and mini-WARN provisions from the sources listed above. The most recent review date is shown in the footer of every page and is currently 2026-04.

What we do not account for

The model is a benchmark, not a forecast. It deliberately does not try to capture:

• Deferred compensation and bonus true-ups.
• Equity acceleration, RSU vesting, or option exercise windows.
• Stock vesting cliffs and the value of in-the-money grants that may or may not be honored at separation.
• Executive employment contracts, change-of-control clauses, non-competes, or individually negotiated severance riders.
• Your individual tax situation: filing status, dependents, other income, deductions, credits, or estimated-tax requirements.
• Anything specific to your situation — medical needs, visa status, location moves, two-income households, or the dynamics inside your company.

For any of those, talk to a qualified professional. The calculator gives you a benchmark to start from. It does not replace advice on your facts.

Last reviewed: 2026-04