Javascript is not enabled.

Javascript must be enabled to use this site. Please enable Javascript in your browser and try again.

Skip to content
Content starts here


Leaving Website

You are now leaving and going to a website that is not operated by AARP. A different privacy policy and terms of service will apply.

Why You Should Fill Out a New W-4 Tax Form Now

Withhold the correct amount from your paycheck to avoid a surprise tax bill

spinner image couple in home setting work together on financial paperwork and look at laptop computer screen
iStock / Getty Images

If you haven't filled out the Internal Revenue Service's new W-4 form — the one that tells your employer how much federal income tax to withhold from your paycheck — don't delay any longer. The Tax Cuts and Jobs Act, passed in December 2017, made enough changes to the tax code that refiguring your federal income tax withholding now could help you dodge a surprisingly big tax bill later.

The IRS rolled out the new form on Jan. 1, 2020, and if you missed it, that's not surprising. People typically fill out the W-4 only when they start a new job. These days, thanks to the coronavirus, few workers are getting hired.

spinner image Image Alt Attribute

AARP Membership— $12 for your first year when you sign up for Automatic Renewal

Get instant access to members-only products and hundreds of discounts, a free second membership, and a subscription to AARP the Magazine.

Join Now

The IRS says the new W-4 is more accurate, which is good. Withholding too little could set you up for a nasty tax bill next year, and penalties as well. Withholding too much is a sure way to get a tax refund, though in reality all you are doing is giving Uncle Sam an interest-free loan. Most experts say it's best to withhold (as closely as you can) the exact amount you owe.

The new form may also take longer to fill out, and doing it accurately can require having access to your tax return from last year as well as your current pay information.

Allowances are history

On the old W-4, you could use personal allowances to raise or lower the amount of taxes your employer withheld from your paycheck. The more allowances you could claim, the less withheld; the fewer allowances, the more withheld. It was confusing for many, especially those new to the workforce, but it was a familiar process to experienced workers.

Those days are past, however: Allowances were tied to personal exemptions, and the Tax Cuts and Jobs Act suspended personal exemptions until 2026. The new tax law boosted the standard deduction substantially, which lowers taxes for many but makes it difficult for most taxpayers to itemize deductions. The standard deduction for single taxpayers in the 2020 tax year is $12,400. It's $24,800 for married couples filing jointly. Those who file as head of household have an $18,650 standard deduction.

Now, if you want to change the amount your employer withholds for taxes, you have to use the new W-4. You'll need to enter your filing status, income from other jobs and the number of dependents you have, among other things. Your employer will figure your tax withholding from that information. You're not required to fill out the new W-4 if you've been in the same job since before Jan. 1, 2020, but doing so will help ensure you don't get stuck with a surprise tax bill. If you start a new job in 2020, you're required to use the new W-4.

A bit more work

Normally, when you get a new job, you're handed a W-4 form to fill out. “If all you do is indicate your expected filing status on Form W-4 and then sign the form, your employer will base withholding on that filing status and standard deduction,” says IRS spokesman Eric Smith. And for many people, that's perfectly adequate.

spinner image close up of blank 2020 W-4 form and a pen
iStock / Getty Images

But if your spouse also works, or if you have children or another job, you'll need more information to fill out the new W-4 accurately. “The best way to make sure you fill it out most accurately is to have last year's return — tax-year 2019, if you've done it — and a recent pay stub at hand,” Smith says. The more information you have, the more accurate your estimate will be.

See more Health & Wellness offers >

Working couples often don't withhold enough for federal taxes because the taxes on their combined incomes are typically higher than what the taxes would be on their income from each job individually. The new W-4 worksheet will tell each spouse how much they should have withheld. Similarly, it will also let them adjust for any deductions, which reduce taxable income, or credits, which reduce taxes dollar for dollar.

If you're receiving unemployment benefits, you can fill out a voluntary W-4V to authorize withholding on your payments. (Many people forget that unemployment compensation is taxable.) You can also use W-4V to authorize withholding on Social Security payments.

Automate the process

While you can fill out the new W-4 worksheets on paper, it's easiest to use the IRS online Tax Withholding Estimator. “It can make your withholding very precise,” Smith says. “If you have good information about your financial situation, it's likely you'll never get a tax surprise."

The tool can handle pension income as well as self-employment income, and it ensures your calculations are correct. The estimator doesn't report your other sources of income to your current employer, so if you don't want them to know you have other income, you don't have to worry. (You can also pay estimated taxes separately, if you want.)

If you want to fly in the face of traditional financial advice and ensure that you get a refund, the IRS tool will let you do that, too, with a slider bar that lets you adjust how much you'll get back. “People love their refunds,” Smith says.

Discover AARP Members Only Access

Join AARP to Continue

Already a Member?