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Paycheck and withholding FAQs

By Barron Hansen, Founder · Updated April 21, 2026

This page is the full Q&A reference for US paycheck math in 2026. Answers cover the same scope the homepage calculator models: federal income tax (10% to 37% across seven brackets, with per-status standard deductions running $16,100 single, $32,200 MFJ, $16,100 MFS, $24,150 head of household), FICA (6.2% Social Security to $184,500, 1.45% Medicare uncapped, 0.9% Additional Medicare above $200,000 single / $250,000 MFJ / $125,000 MFS / $200,000 HoH), state income tax (nine no-tax states, 16 flat-rate, 26 progressive jurisdictions including DC, with five states publishing distinct head-of-household schedules), supported local layers (NYC, Philadelphia, Detroit, Louisville, Pittsburgh and 60-plus others), and pre-tax deduction effects on take-home. The page is organized into five themed sections: federal taxes, state and local taxes, pre-tax deductions, filing status, and payroll mechanics. Each FAQ answer leads with a direct answer in the first sentence so search-engine result pages and voice-assistant responses can lift it cleanly. For source links and validation steps, see the methodology page. For term-by-term definitions, see the glossary. To run a specific case, use the calculator on the homepage.

Federal taxes

The federal layer that applies identically in every US state, driving the largest withholding line on most paychecks.

How are federal tax brackets applied to my income?+
Federal brackets apply progressively to taxable income, not gross. After the standard deduction ($16,100 single, $32,200 MFJ in 2026), each slice of remaining income falls into a bracket and is taxed at that rate. The 22% bracket only hits the slice above the 22% threshold; income below stays in lower brackets at 10% and 12%.
What's the 2026 standard deduction?+
The 2026 federal standard deduction is $16,100 for single filers, $32,200 for married filing jointly, and $24,150 for head of household. Filers age 65 and older or blind get additional standard deduction amounts on top. Most workers take the standard deduction; itemize only if your deductible expenses (SALT, mortgage interest, charity) exceed the standard amount.
How does the Additional Medicare Tax work?+
The Additional Medicare Tax is a 0.9% surtax on wages above $200,000 single ($250,000 married filing jointly). Employers withhold the surtax on every paycheck once a single employee's year-to-date wages exceed $200,000, regardless of filing status. Any over- or under-withholding gets reconciled on the federal return at the household-income threshold.

State and local taxes

Where you live and where you work drive the biggest take-home swings between paychecks of the same gross.

Why does my take-home differ by state?+
Federal income tax and FICA hit identically nationwide, but state structure varies widely. Nine states have no broad-based personal income tax, 16 apply a flat rate, and 26 (with DC) run progressive brackets. The same $100,000 salary can produce a $5,000 to $10,000 take-home gap between a no-tax state and a high-tax state.
Which states tax wages and which don't?+
Nine US states levy no broad-based personal income tax on wages: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. The remaining 41 states plus DC tax wage income. Washington taxes high-income capital gains but not wages. New Hampshire's old Interest and Dividends Tax was fully phased out.
Do I owe state tax in two states if I commute?+
Yes, but only one state collects in most cases. If you live in one state and physically work in another, you typically owe non-resident tax to the work state, then claim a credit for taxes paid against your home state's tax. Reciprocal-agreement pairs (Illinois/Indiana, Ohio/Pennsylvania, Maryland/DC, several Midwest neighbors) skip the work-state step entirely.
What's the difference between flat and progressive state tax?+
Flat-rate states apply a single percentage to every wage dollar, so the marginal and effective state rates are the same number across all incomes. Progressive states use a bracket schedule where the rate steps up as income rises, so the top slice gets taxed at a higher marginal than the effective rate that averages the whole salary.

Pre-tax deductions

Retirement and health-savings contributions that change federal (and most state) taxable income before the brackets apply.

How does a 401(k) reduce my taxes?+
Traditional 401(k) contributions are pre-tax and reduce federal taxable income at your marginal rate. The 2026 employee limit is $24,500 ($31,000 with the age-50 catch-up). At the 22% federal bracket, maxing the deferral cuts federal tax by about $5,390 per year. Most states honor the federal exclusion; New Jersey is a notable exception.
What's the 2026 HSA limit?+
The 2026 HSA contribution limit is $4,400 for self-only coverage and $8,750 for family coverage. Workers age 55 and older can add a $1,000 catch-up contribution. HSA contributions are pre-tax for federal and most state purposes, withdrawals for qualified medical expenses are tax-free, and balances roll over year to year without expiring.
Does a pre-tax 401(k) reduce state tax in every state?+
Almost. Most states honor the federal pre-tax exclusion, so a 401(k) deferral that reduces federal taxable income also reduces state taxable income. New Jersey is the main exception: the state taxes 401(k) contributions as wages in the year contributed and exempts qualified distributions later. Pennsylvania has similar quirks on certain plan types.

Filing status

The choice that determines which bracket schedule, standard deduction, and credit thresholds apply to a return.

How does MFJ vs single change my take-home?+
Married filing jointly typically takes home several thousand dollars more per year than single at the same gross. The federal MFJ brackets are roughly twice as wide as single (until the 32% bracket), and the standard deduction doubles. Most progressive-tax states widen their brackets for joint filers too. Flat-rate states stay filing-status-neutral on rates.
What's the difference between MFJ and MFS?+
Married filing jointly (MFJ) combines both spouses' income on one return, using the wider joint bracket schedule. Married filing separately (MFS) files two returns at narrower brackets. MFS is rarely advantageous; it tends to disable several credits (EITC, education credits, IRA deductibility above limits) and uses an effectively lower SALT cap per filer.

Payroll mechanics

Why a clean calculator estimate may not match the exact figure on a real pay stub.

Why is my pay stub different from this estimate?+
Pay stubs reflect employer-specific payroll system rounding, your exact W-4 elections, mid-year salary changes, bonus or supplemental wage handling, employer-paid benefits that show up on the stub, and pay-period timing. The calculator estimates a clean annualized result for a steady-state W-2 salary; real paychecks combine many one-off and per-period adjustments.
What's the difference between gross, taxable, and net pay?+
Gross pay is your full salary before any deductions. Taxable income is gross minus pre-tax deductions (401(k), HSA, qualified benefits) and the standard deduction (or itemized); this is what federal brackets actually apply to. Net pay (take-home) is gross minus all taxes (federal, FICA, state, local) and post-tax deductions, the figure that hits your bank account.

Reviewed

How This Page Is Reviewed

FAQ answers are reviewed against current source materials and updated when the calculator logic or supported tax assumptions change.

Reviewed by

PaycheckCalc Research Desk

Last reviewed

2026-04-21

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