How this calculator works
Tax year: 2026, United States. Federal income tax is calculated on salary less the pre-tax 401(k) deferral and the standard deduction, using the filing-status brackets. Social Security is 6.2% of salary up to the $184,500 wage base. Medicare is 1.45% of all salary, plus 0.9% above $200,000 for single and head-of-household filers, $250,000 for joint filers and $125,000 for married filing separately. The deferral reduces income tax but not Social Security or Medicare, which is how a traditional 401(k) works. The model leaves out state and local income tax, other pre-tax benefits such as health insurance, tax credits, other income, withholding and employer contributions. It assumes the filer is under 65, so the age addition to the standard deduction is not applied.
Formula
Federal taxable income = max(0, salary - deferral - standard deduction). Federal tax = brackets applied to that figure. Social Security = 6.2% x min(salary, 184,500). Medicare = 1.45% x salary + 0.9% x max(0, salary - status threshold). Take-home pay = salary - deferral - federal tax - Social Security - Medicare. Per period = annual take-home pay / pay periods.
Worked example
A single filer earning $75,000 with no deferral has $58,900 of federal taxable income and $7,670 of federal income tax. Social Security is $4,650 and Medicare is $1,087.50, so total federal deductions are $13,407.50, annual take-home pay is $61,592.50 and biweekly pay is $2,368.94.
Frequently asked questions
Why is the 401(k) deferral not taken out of Social Security?
Traditional 401(k) deferrals are exempt from income tax but not from FICA. Only certain pre-tax benefits, such as employer health insurance under a cafeteria plan, reduce Social Security and Medicare wages.
Is state tax included?
No. State and local income tax is not modelled, so residents of states with income tax will take home less than shown. This page models the federal side only.
What does the additional Medicare tax apply to?
The 0.9% rate applies to wages above the filing-status threshold. Unlike Social Security, there is no wage ceiling on Medicare, so the extra rate continues for all wages above the threshold.
Does this include credits or other income?
No. Credits, a spouse's income, investment income and withholding are excluded. The result is an estimate of the federal tax on this salary alone.