Form W-4: Employee's Withholding Allowance Certificate

The W-4 is based on the idea of "allowances." The more allowances you claim, the less money your employer will withhold for taxes. You get one allowance for yourself, one for your spouse, and one for each dependent you report on your tax return.

You can claim additional allowances in certain cases such as when you itemize your deductions, claim a filing status of "head of household", or if you’re eligible to claim a tax credit for child care expenses.

The W-4 also helps you determine whether you need extra money withheld from your pay. If you work more than one job, have self-employment income, or if your spouse earns income too, the standard calculations made on Form W-4 may be inaccurate, resulting in not enough tax being withheld. By voluntarily increasing your tax withholding on the W-4, you can avoid having to make an additional lump-sum tax payment when you file.

The W-4 form includes a series of worksheets you can use to calculate the appropriate number of allowances to claim. This includes a separate worksheet for taxpayers who have a working spouse, or earn other types of income.

After calculating your allowances, you must provide some personal information, and report your total allowances and additional withholding amounts on the actual form. You must tear off this certificate and provide it to your employer.

You can also use the W-4 to declare yourself exempt from withholding, meaning your employer will not withhold any federal income tax from your wages. You can claim an exemption from withholding only if you had no income tax liability in the prior year, and you don’t expect to owe any tax in the current year.

For example, if you are a single taxpayer who earns approximately $8,000 every year, then you will not owe federal income tax because of the personal exemption and standard deduction you can claim on your tax return, which effectively eliminates the possibility of owing tax on your $8,000 of earnings.

The IRS recommends that if you work more than one job, or if you and your spouse both work, that you claim all your allowances on the W-4 for the highest-paying job, and claim zero allowances on the W-4 forms for all other jobs. It also suggests that taxpayers consider completing a new W-4 every time a major life event occurs, such as a marriage, the birth or adoption of a child or a spouse getting or losing a job. These things can have a direct effect on the amount of tax you owe, so your W-4 should account for them.