Taxes & Deductions

What Are Payroll Deductions? A Simple Breakdown

Every time you receive a paycheck, a portion of your gross pay is withheld for taxes and benefits before the remainder reaches your bank account. These are payroll deductions — and understanding them is essential for managing your finances, maximizing your benefits, and avoiding tax surprises.

The Two Categories of Payroll Deductions

All payroll deductions fall into one of two categories: mandatory deductions required by law, and voluntary deductions you elect through your employer. Both can be further divided into pre-tax and post-tax deductions.

Mandatory Payroll Deductions

Your employer is legally required to withhold these from every paycheck. You cannot opt out of mandatory deductions.

Federal Income Tax

Withheld based on your W-4 elections and the IRS withholding tables. The amount depends on your gross pay, pay frequency, filing status, and any additional withholding requested. Federal income tax uses a progressive bracket system: 10%, 12%, 22%, 24%, 32%, 35%, and 37% for 2026. The withholding system estimates your annual tax liability and spreads it across pay periods throughout the year.

Social Security Tax (OASDI)

A flat 6.2% is withheld from your wages up to the annual Social Security wage base — $176,100 in 2026. Your employer matches this 6.2% contribution on your behalf, for a total of 12.4% going toward Social Security. Once your YTD wages exceed the wage base, Social Security withholding stops for the rest of the calendar year.

Medicare Tax

A flat 1.45% is withheld on all wages with no cap. Your employer also pays 1.45%, making the total Medicare contribution 2.9%. Individuals earning more than $200,000 (single) or $250,000 (married filing jointly) pay an additional 0.9% Additional Medicare Tax, for which the employee pays the full amount — employers do not match the additional 0.9%.

State Income Tax

Required in 41 states plus D.C. Rates range from a flat 2.5% (Arizona) to a progressive rate reaching 13.3% (California). Nine states have no wage income tax: Alaska, Florida, Nevada, New Hampshire, South Dakota, Tennessee, Texas, Washington, and Wyoming. State withholding is based on your state's equivalent of the W-4 form.

Wage Garnishments

Court-ordered deductions for child support, alimony, student loan default, or tax levies. Employers are required to comply with valid garnishment orders. Federal law limits garnishments to 25% of disposable earnings for most debts; child support can be up to 65% of disposable earnings.

Voluntary Pre-Tax Deductions

These deductions reduce your taxable income — you elect them during open enrollment or onboarding, and they're withheld before taxes are calculated.

401(k) / 403(b) Traditional Contributions

$23,500 in 2026 (+$7,500 catch-up if 50+)

Reduces federal and state taxable income. Investments grow tax-deferred until withdrawal in retirement.

Health Insurance Premiums

Varies by plan and employer

Employer-sponsored health premiums paid through a Section 125 plan are exempt from federal, state, and FICA taxes.

HSA (Health Savings Account)

$4,300 self-only / $8,550 family in 2026

Triple tax advantage: contributions are pre-tax, growth is tax-free, and withdrawals for qualified medical expenses are tax-free.

FSA (Flexible Spending Account)

$3,300 healthcare FSA in 2026

Pre-tax contributions for healthcare or dependent care expenses. Use-it-or-lose-it rules apply (some plans offer a grace period or limited rollover).

Commuter Benefits

$325/month transit + $325/month parking (2026)

Pre-tax deductions for qualified public transit passes or parking near your workplace.

Dependent Care FSA

$5,000 per household

Pre-tax funds for childcare, preschool, or adult dependent care while you work.

Voluntary Post-Tax Deductions

These are taken after taxes are calculated and don't reduce your taxable income — but they serve other financial purposes.

Roth 401(k): Contributions are post-tax but growth and qualified withdrawals in retirement are tax-free. Same annual limit as traditional 401(k).

Life Insurance (above $50,000): Premiums for coverage exceeding $50,000 are post-tax because the IRS considers the excess coverage a taxable benefit.

Disability Insurance (employee-paid): If you pay disability insurance premiums post-tax, any future benefit payments you receive will be tax-free.

After-Tax 401(k): Some plans allow after-tax contributions beyond the standard limit (up to $69,000 total in 2026). These can be rolled to a Roth IRA via the "mega backdoor Roth" strategy.

Union Dues: Typically a fixed amount per pay period. May be deductible as a job-related expense in some states that allow it.

How Deductions Affect Your Taxes: A Real Example

Annual salary: $70,000 | Biweekly | Single | California

Gross pay per period$2,692.31

− 401(k) 6% pre-tax$161.54

− Health insurance pre-tax$100.00

Taxable wages$2,430.77

− Federal income tax (est.)$298.77

− California state tax (est.)$115.92

− Social Security 6.2%$150.62

− Medicare 1.45%$35.24

Net Pay$1,830.69

The pre-tax 401(k) and health insurance deductions reduced taxable wages by $261.54, saving roughly $57 in federal and state taxes that period — about $1,485 per year.

How to Optimize Your Payroll Deductions

1
Contribute at least enough to your 401(k) to capture the full employer match — it's a 50–100% instant return on investment.
2
Max out your HSA if you're on a high-deductible health plan. It's the only account with a triple tax advantage.
3
Use a dependent care FSA if you have children in daycare — $5,000 in pre-tax contributions can save over $1,000 in taxes.
4
Review your W-4 after any major life change (marriage, child, second job) to avoid under- or over-withholding.
5
If your total itemized deductions exceed the standard deduction, talk to a tax advisor about which deductions to prioritize.

See How Deductions Affect Your Take-Home Pay

Use our free paycheck calculator to estimate the impact of your salary and tax situation on your net pay. It covers all 50 states with 2026 federal and state tax brackets.