How to Fill Out a W-4 Form for a New Job

African American woman sitting at table completing paperwork
JodiJacobson / Getty Images

If you have landed your first job or are starting a new job you will need to fill out a W-4 form so that your employer can determine how much tax to withhold from your paycheck. The Personal Allowances Worksheet accompanying your W-4 form will be a valuable tool to help you determine the number of allowances you should note on the actual form.

What a W-4 Form is For

The W-4 Form is completed by an employee so the employer can withhold the correct amount of federal income tax from your pay.

When you are hired for a new job, you will be required to complete a W-4 Form to let your employer know how much tax to withhold.

Prior to starting employment, you can fill out a PDF version form online and print it out.  It's also a good idea to review withholding amounts on a regular basis to ensure the appropriate amount of tax is withheld.

The W-4 form indicates to employers how much they need to deduct from your wages for federal income tax. This amount can be altered significantly depending on the number of withholding allowances a person decides to claim.

The more claims taken, the less money will be taken out of your paycheck for federal taxes. These allowances can be changed at any time on account of additional jobs, marriage, pregnancy or adoption, divorce, etc.

W-4 Allowances

Allowances will be increased if you claim yourself, a spouse or children as dependents.. Paying child care expenses may also add to your number of allowances as will non-wage income like dividends or interest.

If you itemize deductions on your taxes, you will want to complete the Deductions and Adjustments Worksheet to see if the level of your deductions indicates that you could decrease the amount that you withhold. The IRS Withholding Calculator walks you through the process of evaluating your situation to determine appropriate levels of withholding.

Before you begin filling out the W-4, it is worth sitting down with your spouse to determine whether or not you will be filing a joint tax return together for the current year. If so, review the first part of the W-4 carefully, as this section will determine how many personal allowances you will claim as a couple. It is best practice to determine the number of allowances in advance so that when you each fill out W-4 forms with your employers, you will only list the half the total allowances (your portion of the join return) when asked.

Once the proper number of allowances and any additional amount of withholding is determined through the use of these tools, the process of completing your W-4 is quite straight forward. Boxes 1 - 4 contain your personal data, box 5 is where you enter the number of allowances, box 6 is the place to put any additional amount you would like withheld and box 7 is only for the rare person who doesn't need to withhold due to a very limited tax liability.

Changing Your Deductions

Even if you haven't just landed a new job, you can file a new W-4 with your employer if your life situation and/or deductions have changed or if you have found that you have too high a tax bill when you file or too large a refund.

A critical ingredient in the process will be your philosophy regarding paying taxes, whether you would prefer to pay as you go throughout the year via withholding or at the end of the year. Some wage earners prefer to withhold more to lessen any tax surprises at the end of the year and in effect, force some savings if they are owed a refund. Others want to maximize their weekly/monthly paychecks and therefore increase their allowances and the amount withheld.

After submitting your W-4 (through new employment or updated with new allowances), the information will go into effect quite fast. Employers are required to update employee information within 30 days of submitting the form, in time for that next pay period. If you forget to submit your W-4 in time for the end of the year, the IRS will treat consider your income like that of a single person without any withholding allowances.

Depending on your situation, this could be crippling, so be sure to submit the form as soon as possible while it is still fresh on your mind.

More New Hire Paperwork: Employment Forms Required for New Hires