WASHINGTON – Change is hard, so can I put on my parent hat?

As you may know, Congress passed some major tax legislation at the end of last year. Actually, it turns out that 26 percent of Americans don’t know this, and about half haven’t heard that income-tax brackets are changing under the new rules as well, according to a recent survey by NerdWallet.

Here’s the thing: I know many of you will not want to do what I’m going to recommend. But like I tell my kids when they come up with excuses for not doing chores: “Do it anyway, and because I said so.”

This is what you need to do. Go to irs.gov and search for “Tax Withholding Calculator.” You’re going to use this updated tool to review and – if necessary – change your W-4 for 2018. This is the form (Employee’s Withholding Allowance Certificate) you fill out to make sure your employer is withholding the correct amount of federal income tax from your paycheck.

If not enough taxes are withheld from your paycheck or you earn additional money that is not subject to payroll taxation, you might owe taxes at tax time. You should aim to have your withholdings match your actual tax obligation.

I tried the calculator. It took me about 20 minutes – mostly because I didn’t have enough information at hand. You need your most recent paystub, your W-2 and information from your 2017 tax return.

The first page of the calculator is not too intimidating. It asks you what filing status you’ll be using on your 2018 income-tax return. Here are your choices: single, married filing jointly, married filing separately, head of household, or qualifying widow.

This simplicity stops at the first page, but don’t be daunted. On the second page, you’ll have to answer questions about how many jobs you and/or your spouse have. You’ll be asked to check boxes if you contributed to a tax-deferred retirement plan (like a 401(k) or similar workplace account). You’re asked if you contributed to a “cafeteria or other pre-tax plan.” There’s a link that explains that it’s asking if you had payroll deductions for such expenses as health or life insurance or a flexible spending account. Throughout the calculator you’ll find hyperlinks to explain terms.

Also on Page 2, there are questions to determine if you qualify for child and dependent credits, such as the child tax credit. Don’t assume you qualify or don’t qualify. My oldest two children are 22 and 19, so my husband and I can’t get the credit for them anymore. But I wasn’t sure about our youngest, who is turning 18 at the end of the summer. Turns out your child has to be under 17 by the end of the tax year to qualify for the child tax credit.

Page 3 is all about your income, and here’s where you input the dollar amounts for retirement contributions. You also enter the federal income tax withheld from your last salary payment, how frequently you’re paid and how long you worked during the year. There’s a section for non-wage earners too.

Page 4 focuses on your deductions. If you plan to itemize and not take the standard deduction, you’ll list medical and dental expenses, gifts to charity, taxes you paid and other deductions. Keep in mind that you can only deduct the amount of your medical and dental expenses that is more than 7.5 percent of your adjusted gross income. And starting this year, you’re only allowed itemized deductions of up to $10,000 ($5,000 for married taxpayers filing a separate return) for state and local income taxes, property taxes or sales taxes.

Finally, on Page 5, you get your results. It’s a good summary. Here’s where you’ll receive information on the recommended allowances to take on your W-4. If you’re not withholding enough money, the calculator suggests how much additional money you may need to have taken out of each paycheck to meet your full estimated tax obligation. Pension recipients, especially those who receive regular monthly checks, can also use the withholding calculator to make sure the right amount of tax is being withheld.

Get it right and you’ll minimize your tax refund. But that’s OK, you don’t want Uncle Sam holding your money interest-free all year, right? At the end of last week, the average refund was $3,103, up slightly from last year at this time, according to the IRS.

With the tax changes taking effect this year, you need to do this paycheck checkup. And no, you can’t wait and do it later.

Michelle Singletary is a columnist for The Washington Post. Readers may contact her at:

michelle.singletary@washpost.com