Your paycheck and withholding

Gross pay is not your pay

Gross pay is what you earned. Net pay (what actually hits your bank account) is gross pay minus several required subtractions, most of which are taxes withheld on your behalf before you ever see the money. Every deduction on a pay stub has a specific name and a specific rule behind it; none of it is arbitrary, even when it feels that way on the first paycheck.

Your first paycheck walks the stub line by line for someone seeing one for the first time. This lesson goes after the two lines that confuse people longest: FICA and withholding.

FICA: the payroll tax you can’t opt out of

FICA (Federal Insurance Contributions Act) funds Social Security and Medicare, and it is separate from income tax withholding. As of 2026, the statutory rates are (irs.gov):

• Social Security tax: 6.2% of wages, but only up to a yearly wage base: $184,500 for 2026. Earnings above that amount owe no additional Social Security tax that year.
• Medicare tax: 1.45% of all wages, with no cap at all.
• Additional Medicare tax: 0.9% on wages above $250,000 for married filing jointly, $125,000 for married filing separately, and $200,000 for everyone else. Your employer starts withholding it once your wages pass $200,000, regardless of filing status, and your return settles any difference. The thresholds are fixed in the tax code, not adjusted for inflation (IRS Q&A).

Your employer withholds these amounts and also pays a matching share on your behalf (employers pay 6.2% and 1.45% too, on top of your wages), so FICA is really a combined 15.3% of wages up to the wage base, split between you and your employer. Unlike income tax, FICA has almost no deductions to reduce it (some pre-tax benefits, such as health premiums paid through a cafeteria plan, are the main exception); it comes out the same way for nearly every employee. If you work for yourself instead, there is no employer to split it with and you owe both halves as self-employment tax, the same 15.3%, worked through in investment and business tax.

Income tax withholding: a running guess

Income tax withholding is different in kind: it is your employer’s best estimate, made all year, of what you’ll actually owe when you file a return in the spring. You control that estimate through Form W-4, which you fill out when hired and can update any time (irs.gov). One thing worth knowing if you learned this before 2020: the W-4 no longer uses withholding allowances at all. The redesigned form asks instead for your filing status, whether you hold multiple jobs, your dependents, and any other income or deductions, and it has a line where you can simply request an extra dollar amount be withheld from each paycheck. Claiming a filing status of “married filing jointly” generally withholds less per paycheck than “single”; adding a second job on the multiple-jobs step, or entering an extra amount, withholds more.

Withholding is a guess because your actual tax bill depends on your whole year (total income, filing status, credits, other jobs), information your employer only partly has. That’s why nearly everyone’s withholding and actual tax owed don’t match exactly, which is resolved when you file.

The refund is not a bonus

When withholding exceeds what you actually owed, the IRS sends the difference back as a refund. It feels like found money, but it is the opposite: it is money you earned during the year, handed to the government early, interest-free, and returned to you months later with no interest paid on it. A large routine refund often means your W-4 is set to over-withhold (refundable credits such as the Earned Income Tax Credit are the other common cause, and that part was never withheld from you). You could have had that money in every paycheck all year instead. The reverse is also true: owing a large balance at filing time usually means withholding was set too low, which can also trigger a penalty for underpayment.

Neither extreme is inherently wrong: some people deliberately over-withhold as a forced-savings habit, but it should be a choice, not a surprise. The IRS’s free Tax Withholding Estimator (irs.gov) walks through your actual situation and suggests a W-4 adjustment to land closer to break-even.

The practice

Pull up your most recent pay stub and find three numbers: gross pay, the Social Security line, and the Medicare line. Confirm the Social Security line is close to 6.2% of gross and Medicare close to 1.45%. If either looks off, it’s worth asking payroll why. Then check when you last updated your W-4; if it’s been more than a year, or your income or household has changed, that’s worth revisiting too.

Try it yourself: open the interactive tool for this lesson.