US take-home pay is gross income minus federal income tax (10-37% bracketed), FICA (6.2% Social Security + 1.45% Medicare + 0.9% Additional Medicare over $200k), state income tax (0-13.3%), and pre-tax deductions (401(k), HSA, FSA). IRS Publication 15 is the authoritative rate reference.

US take-home pay has more moving parts than most countries because of the federal-state stack, the choice between pre-tax and post-tax retirement contributions, and the relatively high mandatory withholding for FICA.

The deduction stack, in order applied:

1. Pre-tax deductions — reduce taxable income for federal and most state purposes: - Traditional 401(k) up to the annual elective deferral limit, plus catch-up over age 50 - HSA, when paired with a High-Deductible Health Plan - FSA (medical and dependent care) - Pre-tax employer health, dental, vision premiums - Commuter benefits

2. FICA — calculated on gross less pre-tax 401(k)/HSA reductions: - Social Security: 6.2% up to the annual wage base (indexed each year — see SSA.gov) - Medicare: 1.45% on all wages - Additional Medicare: 0.9% on wages above $200k single / $250k MFJ

3. Federal income tax — seven brackets, 10% / 12% / 22% / 24% / 32% / 35% / 37%, with the standard deduction subtracted first (or itemised deductions where higher). IRS publishes brackets each November for the following year.

4. State income tax — ranges from 0% (TX, FL, NV, WA, TN, SD, WY, AK; NH and WA tax only investment income) up to 13.3% (CA top bracket). Some states (NY, NJ, CT, OR, CA) also stack a SDI or similar payroll levy.

5. Post-tax deductions — Roth 401(k), Roth IRA, disability insurance, supplemental life.

The calculator handles all 50 states plus DC, all four W-4 filing statuses (single, MFJ, MFS, HoH), the pre-tax vs. post-tax retirement allocation toggle, and the Additional Medicare and Net Investment Income Tax thresholds for higher earners. Output includes annual gross-to-net, monthly take-home, marginal rate on the next dollar earned (useful for raises, RSU vests, and bonus-tax-rate decisions), and effective rate.

For underlying rate schedules, IRS Publication 15, Publication 17 (Your Federal Income Tax), and the SSA wage-base announcement are the authoritative federal references; state revenue departments publish their own bracket tables.