Understanding Your Paycheck Deductions (Finally)

You negotiated a $75,000 salary. Your first paycheck is $4,500, not $6,250. Where did $1,750 go? The deduction breakdown on your pay stub exists, but it reads like a tax code reference manual.

Here's what each line actually means.

The Big Three: Federal, State, and FICA

Federal income tax is the biggest variable — it depends on your income level, filing status, and what you put on your W-4. The IRS withholding tables estimate how much you'll owe for the year and collect it gradually through your paychecks.

FICA is the two lines that never change: Social Security (6.2%) and Medicare (1.45%). Together they take 7.65% off the top. No deductions or credits reduce FICA; it's calculated on gross wages up to the wage cap. These fund Social Security retirement benefits and Medicare — you'll eventually get something back for them, unlike income tax which funds general government operations.

State income tax varies from 0% (Texas, Florida, Tennessee) to 13.3% (California's top rate). If you live and work in a state with no income tax, you get back 0–9% of your gross pay depending on which state you moved from.

Pre-Tax vs Post-Tax Deductions

Pre-tax deductions come out before taxes are calculated — they reduce your taxable income. Post-tax deductions come out after taxes — they don't affect your tax bill. This distinction matters more than most people realize.

• Pre-tax (reduce your taxes): 401(k) traditional contributions, health/dental/vision insurance premiums, HSA contributions, FSA contributions, transit/parking benefits
• Post-tax (do not reduce taxes): Roth 401(k) contributions (the Roth portion), life insurance above IRS limits, wage garnishments, union dues

The W-4: The Form That Controls Your Withholding

Many people set this once when they start a job and never touch it again. That's fine if nothing changes. But life events — marriage, divorce, having a child, taking on a second job, a significant pay increase — all change your tax situation. If you owed a large amount in April or got a huge refund, your withholding is off. A large refund sounds nice but it means you gave the government an interest-free loan all year.

The Numbers That Affect Your Bottom Line

• Single filer, $75,000 salary, no pre-tax deductions: approximately $56,000-$58,000 take-home depending on state
• Same salary with $10,000 in 401(k) contributions: saves roughly $2,200 in federal taxes, take-home decreases by only $7,800 despite $10,000 going to retirement
• Adding an HSA contribution of $3,000: saves another $660 in federal taxes