What Is a FITW Deduction?

You pay your income taxes all through the year, not just at tax time.

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FITW is an abbreviation for "federal income tax withholding." You'll sometimes see it on payroll stubs to identify your withholding deductions. Withholding is one way of paying income taxes to the federal government before your end-of-the-year tax filing.

Your FITW is one of several deductions from your take-home pay each pay period. These are different from the deductions you're allowed to take annually when you fill out your tax return, which reduce your taxable income.

Income Tax

Income tax is a pay-as-you-go system in the U.S. You pay taxes during the year as your income is earned rather than in a lump sum at the end of the year. Payments are generally made as federal income tax withholding deductions from a worker's paycheck. Income earners who don't receive a paycheck, such as a self-employed business owner, are typically required to pay estimated taxes quarterly in lieu of income tax withholding.

Form W-4

Your employer probably had you fill out a Form W-4 from the U.S. Internal Revenue Service to establish the amount of FITW deductions from your paychecks. Along with your salary information, this form gives your employer the information he needs to calculate your withholding amount.

You can update your W-4 information at any time if your circumstances change and you want to increase or decrease the withholding amounts from your paychecks.

The Withholding Amount

You're required to withhold from your pay an amount that reasonably anticipates your annual income tax obligations. The actual amount withheld depends on your income as well as the information you provide on your Form W-4, such as your marital status. A smaller amount is withheld if you file an income tax return jointly as a married couple rather than as a single taxpayer.

The more exemptions you claim for dependents, the less your withholding will be. You can increase or decrease withholding depending on your financial situation. For example, if you have other sources of income apart from your employment, you can increase your withholding as a way of paying the additional tax that is due on that inccome. Conversely, if you have large, deductible expenses during the year, you can lower your withholding amount in anticipation of owing less tax. You can use an IRS online withholding calculator to make the best determinations.

Other Deductions

Your FITW is only one of several types of deductions taken from your paycheck. You also have deductions for additional federal obligations such as Social Security and Medicare and deductions for state income tax. You might also have non-government deductions, such as funds withheld for union dues, health insurance or retirement plan contributions.