The IRS is still encouraging people to check their withholding to make sure their refund expectations align with reality. Tax professionals also say withholding should be adjusted at major life events: marriage, the birth of a child, a significant raise or when changing how much of a salary is allocated to a retirement account.

Child Credit

Middle-class families with simple situations seem most likely to get pleasant news, thanks to the new $2,000 child tax credit. For more affluent taxpayers, their refund will depend on the complex interplay of lower rates, the easing of the AMT and new deduction limits.

The SALT cap has gotten the most attention from taxpayers in states like New York and California with high income and property taxes, but their angst will be offset by changes to the AMT, which prevented many of them from deducting their full state and local tax burden anyway.

The IRS is trying to soften the blow of all the refund confusion. This year, the IRS will waive the penalties for those who paid at least 85 percent of their tax liability, down from the usual 90 percent.

Taxpayers fearful of how much they owe are better off to file and not pay immediately than not to submit a return at all.

“The failure-to-file penalties are the worst," said Harvey Bezozi, a CPA in Boca Raton, Florida.

Middle-Class Woes

The confusion is likely to do little to sway public opinion in favor of the new law. Republicans acknowledged in an internal poll before the 2018 midterms that they’d lost the messaging battle on tax cuts. The law has consistently struggled to poll above 50 percent approval.

Representative Peter King, a New York Republican who broke from his party and voted against the 2017 tax law, said he has already heard from constituents complaining that they’re paying more this year.