Does my 401(k) reduce my Social Security tax?

No. Pre-tax 401(k) reduces federal income tax wages, not FICA wages.

Depends on your current vs expected retirement tax bracket. Lower in retirement = pre-tax wins. Higher = Roth wins. Many people split because future brackets are unknown.

Is the employer match free money?

Yes, after vesting. Always contribute enough to capture the full match. Leaving before vesting forfeits unvested match.

Why didn't my 401(k) reduce my Medicare tax?

Pre-tax 401(k) is not exempt from FICA (Social Security + Medicare). It is exempt from federal income tax.

401(k) Deductions on Your Paycheck

Workplace retirement saving via your paycheck. Pre-tax cuts your taxable wages now and you pay tax in retirement. Roth flips that. Employer match is on top either way.

PayslipIQ provides educational information and estimated calculations only. It does not provide tax, legal, financial, accounting, employment, benefits, or payroll advice. PayslipIQ is not a CPA firm, law firm, financial advisor, payroll provider, or tax authority. Always verify your paycheck, deductions, withholdings, and tax position with your employer's payroll department, a qualified CPA, the IRS, your state tax authority, or another appropriately qualified professional. Calculations are estimates; your actual paycheck may differ based on factors specific to your employer, location, benefits elections, and personal tax situation.

Pre-tax (traditional) 401(k)

Reduces federal income tax wages and most state income tax wages. Does NOT reduce FICA wages. You pay tax when you take qualified distributions in retirement (age 59.5+, or under hardship rules).

Roth 401(k)

Post-tax. No reduction in current taxable wages. Qualified withdrawals (account 5+ years old, age 59.5 or other qualifying event) are tax-free in retirement. FICA applied on the contribution.

The shared annual limit

The IRS sets a combined annual employee contribution limit across pre-tax and Roth. The 2026 limit is $24,500. Verify the current year at irs.gov.

Catch-up contributions

Age 50+ catch-up: extra contribution allowed once you turn 50 in the calendar year. The 2026 catch-up is $8,000.
SECURE 2.0 super catch-up at 60-63: a higher catch-up amount, $11,250 for 2026.

Employer match

Money your employer puts in on top of yours. Common formulas: dollar-for-dollar up to 4 percent of your pay, or 50 cents on the dollar up to 6 percent. Check your plan documents.

Match goes into a pre-tax sub-account regardless of whether your contribution is pre-tax or Roth. Some plans (under SECURE 2.0) offer Roth match.

Vesting

Your contributions are always 100 percent vested. Employer match may have a vesting schedule (often 3-year cliff or 6-year graded). Leaving before vesting forfeits unvested match.

The combined limit

Total of employee contributions plus employer match plus profit-sharing into one plan is capped at the IRS Section 415(c) limit ($72,000 for 2026, plus catch-up).

401(k) loans

Most plans allow loans up to 50 percent of your vested balance, capped at $50,000. You repay yourself with interest via payroll deductions, post-tax. Default on a 401(k) loan triggers tax + 10 percent early withdrawal penalty if you are under 59.5.

Highly Compensated Employees

HCEs (employees earning above an IRS threshold) may face additional restrictions if their plan fails non-discrimination testing.

Frequently asked questions

Does my 401(k) reduce my Social Security tax?: No. Pre-tax 401(k) reduces federal income tax wages, not FICA wages.
Pre-tax or Roth?: Depends on your current vs expected retirement tax bracket. Lower in retirement = pre-tax wins. Higher = Roth wins. Many people split because future brackets are unknown.
Is the employer match free money?: Yes, after vesting. Always contribute enough to capture the full match. Leaving before vesting forfeits unvested match.
Why didn't my 401(k) reduce my Medicare tax?: Pre-tax 401(k) is not exempt from FICA (Social Security + Medicare). It is exempt from federal income tax.