Your paycheck shrinks because of federal income tax, Social Security tax, Medicare tax, and sometimes state and local taxes

The amount that leaves your paycheck before you see it depends on four things: how much you earn, what you told your employer on Form W-4, which state you live in, and whether your city collects income tax. Federal withholding alone typically takes 10 to 24 percent of your gross pay, depending on your tax bracket and W-4 choices. Social Security takes 6.2 percent and Medicare takes 1.45 percent — these are fixed percentages that come out of almost every paycheck. If you live in a state with income tax (41 states do), that can add another 2 to 13 percent depending on where you are and what you earn.

The reason money comes out before you receive your check is that your employer is required by law to withhold taxes and send them to the IRS and your state on your behalf. This is not optional — it happens automatically based on the W-4 form you filled out when you were hired. The goal is to have enough withheld throughout the year so you do not owe a large bill when you file your tax return in April, and ideally so you get a refund.

Key Takeaways

  • Federal income tax withholding ranges from 10 to 24 percent of your paycheck depending on your income level and W-4 choices, and is separate from Social Security and Medicare taxes.
  • Social Security tax is always 6.2 percent of your gross pay, and Medicare tax is always 1.45 percent, up to certain income limits for Social Security.
  • State income tax (where it exists) and local income tax (in some cities) are additional deductions that vary widely by location.
  • Changing your W-4 at any time during the year changes how much is withheld from your next paycheck onward, which affects your take-home pay when ready.
  • The amount withheld is not the same as what you actually owe in taxes — you may get money back or owe more when you file your return.

How federal income tax withholding is calculated

Your employer uses the W-4 form you completed to calculate federal withholding. The form asks you to claim dependents, note if you have multiple jobs, and indicate whether you want extra money withheld each pay period. The IRS provides your employer with tax tables that show how much to withhold based on your filing status, pay frequency, and the number of allowances or adjustments you claimed.

If you claimed zero allowances on your W-4, more money is withheld. If you claimed the number of dependents you actually have, less is withheld. The withholding is designed to approximate what you will owe when you file your return, but it is an estimate — it does not account for income from side work, investment gains, or other sources that only show up when you file. You can change your W-4 at any time by giving a new form to your payroll department, and the new withholding takes effect on your next paycheck.

Social Security and Medicare taxes are fixed percentages

Unlike federal income tax withholding, which varies based on your W-4, Social Security and Medicare taxes are set by law. Social Security tax is 6.2 percent of your gross pay, up to a wage base limit that changes each year (in 2024 it is $168,600). Once you earn more than that in a calendar year, Social Security tax stops being withheld from your remaining paychecks. Medicare tax is 1.45 percent of all your gross pay with no upper limit.

If you earn over $200,000 as a single filer (or $250,000 if married filing jointly), an additional 0.9 percent Medicare tax is withheld. This additional tax does not have a cap and continues for the rest of the year. These percentages are the same whether you are paid weekly, biweekly, or monthly — your employer divides your annual rate by the number of pay periods and withholds that amount each time.

State and local income taxes vary by where you live

Nine states have no income tax at all: Alaska, Florida, Nevada, South Dakota, Tennessee, Texas, Washington, Wyoming, and New Hampshire (which taxes only dividends and interest, not wages). The remaining 41 states collect income tax, and the rates range from 1 percent to over 13 percent depending on your income level and state. Some states use a flat rate — everyone pays the same percentage — while others use brackets similar to federal tax.

In addition to state tax, some cities and counties collect local income tax. Ohio, Pennsylvania, Kentucky, and a handful of other states allow municipalities to impose their own income tax on residents and sometimes on people who work in the city but live elsewhere. Local rates are typically 1 to 2 percent. Your employer withholds state and local tax based on where you live and work, and the amount is shown separately on your pay stub.

What your pay stub shows and what it means

Your pay stub breaks down your gross pay (the total before any deductions) and lists each deduction separately. You will see federal withholding labeled as "FIT" or "Federal Income Tax", Social Security as "FICA-SS" or "Social Security", and Medicare as "FICA-Med" or "Medicare". State and local taxes appear as separate line items. Some pay stubs also show year-to-date totals, which tell you how much has been withheld so far in the calendar year.

Your net pay or take-home pay is what remains after all deductions. This is the amount that actually deposits into your bank account. If you have other deductions — health insurance premiums, retirement contributions, garnishments, or union dues — those also reduce your net pay. The pay stub is your record of what was withheld, and you should keep it to verify that the amounts match what appears on your W-2 at the end of the year.

Why withholding does not equal what you actually owe

The amount withheld from your paycheck throughout the year is an estimate of your tax bill, not your actual bill. When you file your tax return, the IRS compares what was withheld to what you actually owe based on all your income, deductions, and credits. If too much was withheld, you receive a refund. If too little was withheld, you owe money.

Withholding can be off for several reasons. If you have a second job, your employer does not know about it, so they cannot account for the additional income when calculating withholding. If you have investment income, rental income, or self-employment income, none of that is reflected in your W-4. If you claim dependents or deductions that change during the year, your withholding may no longer be accurate. If you are married and both spouses work, the combined withholding from both jobs might be too high or too low depending on how you each filled out your W-4s.

Adjusting your withholding if your take-home pay is too low or too high

If you find that too much is being withheld and you want more take-home pay, you can claim more allowances on a new W-4 form. If too little is being withheld and you want to avoid owing money at tax time, you can claim fewer allowances or request that an extra dollar amount be withheld each pay period. You can also adjust your withholding if your life changes — a new job, marriage, divorce, birth of a child, or a significant change in income.

To change your withholding, complete a new Form W-4 and give it to your payroll or human resources department. The change takes effect on your next paycheck. You can make this change as many times as you need during the year. Keep in mind that if you are trying to avoid a large tax bill, it is better to adjust early in the year so the extra withholding spreads across multiple paychecks rather than waiting until December.

Frequently Asked Questions

Why does my paycheck show different withholding amounts each month?

If your pay varies — for example, if you earn commissions, bonuses, or overtime — your gross pay changes, and so does the federal withholding calculated from it. Social Security and Medicare are percentages of gross pay, so they also fluctuate. State and local taxes do the same. If your withholding is consistent but your gross pay varies, that is normal and expected.

Can I claim zero on my W-4 to get a bigger refund?

Yes, claiming zero allowances increases federal withholding and usually results in a larger refund, but it also reduces your take-home pay throughout the year. This is a choice between having more money now or more money back in April. There is no tax advantage to either approach — you are just timing when you receive your money.

What happens if I do not fill out a W-4?

If you do not provide a W-4, your employer is required to withhold taxes as if you claimed zero allowances, which is the highest withholding rate. You should complete and return the form to your employer as soon as possible so your withholding reflects your actual situation.

Do self-employed people have taxes withheld from their paychecks?

No. Self-employed people do not have an employer to withhold taxes, so they are responsible for paying estimated taxes quarterly to the IRS. This is separate from income tax withholding and is calculated based on expected annual income and tax liability.

If I get a large refund, does that mean I am paying too much in taxes?

A refund means you had too much withheld during the year, not that you paid too much in taxes. Your actual tax bill is the same either way. A large refund means you could adjust your W-4 to have less withheld and increase your take-home pay throughout the year, though some people prefer to over-withhold as a way to save.