Withholding & Planning · 2025
Paycheck Tax Breakdown Calculator
Enter your gross pay and W-4 settings to see a line-by-line paycheck deduction breakdown — federal income tax withholding (IRS Publication 15-T), Social Security (6.2%), Medicare (1.45%), and optional state income tax, with net pay and annual totals shown alongside.
Your paycheck information
Before taxes — your salary ÷ pay periods
Higher withholding when you or your spouse have multiple jobs
Estimates state income tax withholding
Informational only — not professional tax advice.
Enter your gross pay per paycheck to see a full deduction breakdown — federal withholding, Social Security, Medicare, and state income tax, with net pay calculated line by line.
Methodology
How each deduction is calculated
Each line on the paycheck stub is computed from its authoritative source. Federal withholding uses IRS Publication 15-T Percentage Method Worksheet 1 (the same method the W-4 Withholding Estimator uses), annualizing your per-period wage, applying your W-4 elections, looking up tentative withholding via the 2025 tax brackets, and dividing back to a per-period amount. FICA is computed as the employee share per IRC §3101: 6.2% Social Security on wages up to $176,100, and 1.45% Medicare on all wages (both annualized then divided by pay periods). State income tax is annualized using the state's 2025 standard deduction and rate schedule, then divided by pay periods.
Formula
Federal withholding per period: Per Pub 15-T Worksheet 1 — see W-4 Withholding Estimator for full steps (annualized wages adjusted for W-4 elections → brackets → ÷ pay periods) Social Security per period: Annual SS = 6.2% × min(annual gross wages, $176,100) Per period = Annual SS ÷ pay periods Medicare per period: Annual Medicare = 1.45% × annual gross wages Per period = Annual Medicare ÷ pay periods Additional Medicare Tax (high incomes only): Per period = 0.9% × max(0, annual wages − threshold) ÷ pay periods State income tax per period: Annual state tax = Apply state 2025 rate schedule (standard deduction) Per period = Annual state tax ÷ pay periods Net pay per period = Gross pay − all per-period deductions above
Tax year scope
This calculator uses 2025 tax year rates: IRS Publication 15-T (Rev. January 2025) for federal withholding; IRS Publication 15 (2025) and the $176,100 Social Security wage base (SSA.gov, October 2024) for FICA; and each state's 2025 revenue department publication for state withholding.
Stated assumptions and limitations
- W-4 Steps 3 and 4 set to zero. This tool uses only Step 1c (filing status) and Step 2 (multiple jobs). If you have dependent credits in Step 3 or additional adjustments in Step 4, your actual federal withholding will be lower. Use the W-4 Withholding Estimator for the full W-4 scenario.
- No pre-tax benefit deductions. 401(k), HSA, health insurance, and FSA contributions reduce taxable wages and therefore withholding — this tool does not model them. Actual take-home pay after voluntary deductions will differ.
- Social Security spread evenly across periods. SS withholding is shown as the annual SS tax divided by pay periods. In reality, withholding stops mid-year once the $176,100 wage base is reached — your paychecks after that point will be higher than shown here.
- State withholding is estimated. Actual state withholding depends on your state W-4 equivalent and your employer's payroll system. Some states use different withholding tables than the bracket method applied here.
Last reviewed: January 2025. Publication 15-T is reissued each January; FICA rates and SS wage base are reviewed after SSA's October COLA announcement.
Frequently asked questions
Why is my federal income tax withholding different from my actual federal income tax owed?
Withholding is an advance estimate — your employer calculates it per paycheck using IRS Publication 15-T's Percentage Method, which annualizes your wages and applies approximate tax brackets. Your actual federal income tax owed is determined when you file your return, based on your total income, actual deductions, credits, and other adjustments for the full year. If your withholding is too high, you get a refund; too low, you owe the balance. The W-4 elections (filing status, Step 2, Steps 3 and 4) let you calibrate how closely your per-paycheck withholding tracks your final liability.
What is the Social Security wage base and how does it affect my paycheck?
The Social Security wage base ($176,100 for 2025) is the annual earnings ceiling above which the 6.2% Social Security tax no longer applies. Once your cumulative wages for the year exceed that threshold, your employer stops withholding Social Security for the remainder of the year — so your net paycheck increases. There is no wage base cap on Medicare; the 1.45% Medicare tax applies to all wages with no ceiling. If your income exceeds $200,000 (single) or $250,000 (married filing jointly), the additional 0.9% Medicare surtax also applies.
How is state income tax withholding estimated here?
This tool estimates state income tax withholding by computing the annual state income tax liability (using each state's 2025 standard deduction and rate schedule, same as the State Income Tax Calculator) and dividing by the number of pay periods. This is the standard approach most employers use for state withholding. The actual amount your employer withholds may differ slightly if your employer uses a different state withholding method, you have a state-specific W-4 equivalent on file, or your state has additional local taxes.
Why doesn't this tool include 401(k) or health insurance deductions?
This tool models tax withholding only — the mandatory government taxes deducted from your paycheck. Voluntary pre-tax deductions like 401(k) contributions, health insurance premiums, FSA elections, and HSA contributions are between you and your employer and vary widely by benefit plan. Those deductions do reduce your federal (and often state) taxable income, which means the federal withholding shown here is slightly conservative for employees contributing to pre-tax benefits. Use the Pre-Tax Contribution Tax Savings Calculator to see the tax impact of those deductions.
Related tools
See your complete 2025 tax picture in one place — federal income tax, Social Security, Medicare, and state income tax combined into a single effective rate and take-home pay figure.
Open tool →W-4 Withholding EstimatorEstimate how much federal tax will be withheld from your paycheck based on your W-4 elections — IRS Publication 15-T Percentage Method, every step shown.
Open tool →Pre-Tax Contribution Tax Savings CalculatorCalculate exactly how much a 401(k), HSA, Traditional IRA, or SEP-IRA contribution saves you in taxes — federal income tax savings, FICA savings where applicable, and net cost after all savings.
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