Pay Stub Tax Calculator: Understanding Federal & State Withholding

How Is Federal Income Tax Calculated on a Pay Stub?

Federal income tax withholding is calculated using the IRS Publication 15-T Percentage Method (source: irs.gov/publications/p15t). The calculation depends on three factors:

1. Filing status: Single, Married Filing Jointly, Married Filing Separately, or Head of Household. Each status has different tax bracket thresholds.
2. Pay frequency: weekly, bi-weekly, semi-monthly, or monthly. The IRS converts your per-period wages to an annual equivalent for bracket placement.
3. Adjusted annual wages: gross annual wages minus the standard deduction for your filing status ($15,000 for Single in 2025).

PayStubHQ implements this exact method. The federal withholding amount on your pay stub represents the per-period portion of your annual tax obligation based on the IRS bracket tables.

How Is State Income Tax Calculated?

State income tax rates vary significantly. Nine states impose no state income tax on wages: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. Other states range from 1.95% (North Dakota) to 8.75% (Oregon).

PayStubHQ applies the effective flat rate for each state. While some states have progressive brackets, the flat rate provides an accurate withholding estimate used by most payroll processors. See rates for your state on our state-by-state directory.

Social Security Tax (FICA)

Social Security tax is 6.2% of gross wages up to the annual wage base limit of $184,500 for 2026 (source: ssa.gov). Once your year-to-date earnings exceed this cap, Social Security withholding stops for the remainder of the year.

For a worker earning $60,000 annually paid bi-weekly, the Social Security deduction is $2,307.69 × 6.2% = $143.08 per paycheck.

Medicare Tax

Medicare tax has two components:

• Base rate: 1.45% of all wages (no cap)
• Additional Medicare Tax: 0.9% on wages exceeding $200,000 annually (source: irs.gov)

Together, a high earner pays 2.35% in Medicare taxes on wages above $200,000.

Example Tax Calculation

Below is a sample breakdown for a single filer in California earning $5,000 per month:

• Gross pay: $5,000.00
• Federal tax (IRS Pub 15-T): approximately $514
• California state tax (7.25%): $362.50
• Social Security (6.2%): $310.00
• Medicare (1.45%): $72.50
• Net pay: approximately $3,741

Try the exact numbers for your situation with our free paycheck calculator, or see how this breakdown looks on all 6 pay stub templates.

Why Tax Accuracy Matters on Pay Stubs

Inaccurate tax calculations are the most common complaint about pay stub generators. Among the top-rated competitor on Trustpilot, 18% of reviews are 1-star, with most citing stubs that "don't pass verification." Verifiers (landlords, lenders, HR departments) know what deduction amounts should look like for a given salary and state.

PayStubHQ uses the official IRS Publication 15-T withholding tables and state-specific rates. If any calculation is incorrect, PayStubHQ offers a 30-day money-back guarantee.

Filing Status Guide

Your filing status affects your federal withholding because it determines which tax brackets apply:

• Single: unmarried, or married and filing a separate return
• Married Filing Jointly (MFJ): lowest effective rate for most couples; wider brackets
• Married Filing Separately (MFS): same brackets as Single in most cases
• Head of Household (HoH): for unmarried individuals who support a qualifying dependent; wider brackets than Single

Frequently Asked Questions

How is federal tax calculated on a pay stub?

Federal income tax on a pay stub is calculated using the IRS Publication 15-T Percentage Method. The IRS converts your per-period wages to an annual equivalent, subtracts the standard deduction for your filing status, and applies the progressive tax brackets. The resulting annual tax is then divided back to your pay period to determine the per-paycheck withholding amount.

Which states have no income tax?

Nine states have no state income tax: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. Workers in these states keep more of their gross pay because no state withholding is deducted from their pay stubs.

What is the Social Security tax cap for 2025?

The Social Security wage base limit for 2025 is $184,500. You pay 6.2% on wages up to this cap. Once your year-to-date earnings exceed this amount, Social Security withholding stops for the remainder of the year (source: ssa.gov).