Updated
How we calculate your US take-home pay
Three layers, computed separately
A US paycheck is not one deduction. Federal income tax, state income tax and FICA are three independent systems with different bases, and the calculator computes each on its own terms before adding them.
Federal income tax applies to income after the standard deduction for your filing status. The brackets are marginal: only the slice of income inside a bracket is taxed at that bracket’s rate. This is the single most misunderstood point in payroll, and it is why moving into a higher bracket never reduces your take-home pay.
State income tax is layered on top. Nine states levy none at all, several use a single flat rate, and the rest run their own brackets with their own deductions. Selecting a state changes only this layer.
FICA stops, income tax does not
Social Security is charged at a flat rate on wages up to the annual wage base, then stops entirely for the rest of the year. Medicare has no ceiling, and an additional Medicare tax applies above a threshold that depends on filing status and is not indexed.
Because Social Security switches off partway through the year for higher earners, real paychecks grow in the later months. The calculator reports the annual position and its monthly average; a payroll system front-loads the contribution.
What the calculator does not do
It does not model local or city income taxes, pre-tax 401(k) or HSA contributions, health premiums, itemised deductions, child tax credits, or multiple jobs. It assumes one employer and a standard W-4.
It is an estimate for guidance, not tax advice. Your actual withholding follows the W-4 your employer holds and the IRS percentage-method tables.
When the figures are updated
Federal brackets, the standard deduction and the Social Security wage base are indexed annually and published in the autumn for the following year. States publish on their own timetable. We update from the published figures, never from press coverage, and every page carries the date of its last revision, drawn from the site’s version history.
Where the figures come from
Every rate and threshold is taken from the following official publications: