How This Paycheck Calculator Works
Your salary and your paycheck are two different numbers, and the gap between them is taxes. This calculator reconstructs that gap from four pieces: federal income tax (the marginal bracket system), FICA payroll tax (Social Security + Medicare), state income tax (a clearly-labeled estimate for your state), and your pre-tax deductions (401(k), HSA), which shrink the income that gets taxed.
The core formula:
take-home = salary − federal tax − FICA − state tax − 401(k) − HSA
then
per paycheck = take-home ÷ pay periods (52 weekly, 26 biweekly, 24 semimonthly, 12 monthly). Take-home is the cash deposited to you — 401(k) and HSA dollars are subtracted because they go to your retirement/HSA accounts, not your bank account.
Worked example: a single filer in California earning $85,000 with $6,000 of traditional 401(k) contributions. Federal taxable income is $85,000 − $6,000 − $16,100 (2026 standard deduction) = $62,900, producing about $8,550 of federal tax through the brackets. FICA applies to the full $85,000 of wages — 401(k) deferrals don't reduce Social Security or Medicare wages — so 6.2% Social Security ($5,270) + 1.45% Medicare ($1,233) = about $6,503. California's estimated state tax at a ~9.3% effective approximation is about $7,905. Total: roughly $22,958 in taxes. The $6,000 401(k) contribution also leaves the paycheck — into the retirement account, not the bank account — so cash take-home is $85,000 − $22,958 − $6,000 = $56,043/year, or about $2,156 per biweekly paycheck. Notice that FICA alone ($6,503) rivals the federal income tax for a middle earner — payroll tax is the quiet half of the tax bite.
A few things this model handles the way the real system does: Social Security tax stops once wages pass the 2026 cap of $184,500 (so high earners keep slightly more late in the year), Medicare has no cap, and an extra 0.9% Medicare tax applies above $200,000 (single) / $250,000 (joint). State tax is the one rough edge — real states use their own brackets, so we use a transparent flat-rate approximation and label it as such.
Practical tips
A $90,000 salary in Texas (no income tax) can beat $100,000 in a high-tax state once state tax is subtracted. Run both states here before you decide a move or a job change.
Payroll HSA contributions cut both income tax and FICA, so each $1,000 contributed costs your paycheck noticeably less than $1,000. Traditional 401(k) contributions cut income tax only — Social Security and Medicare still apply to those dollars.
If you earn over $184,500 in 2026, your late-year paychecks get a small bump when 6.2% Social Security withholding stops. Don't mistake it for a raise — it resets every January.
Paid every two weeks? Twice a year you'll get three paychecks in a month. Budget on two-per-month and treat the third as pure savings or debt payoff.
Marriage, a new state, a raise, or a new baby all change withholding. Re-run your numbers and update your W-4 so you don't over-withhold (interest-free loan to the IRS) or under-withhold (surprise bill in April).