The tax season might be a little more complicated for filers in certain states.

The recent move by the IRS to extend the filing season to May 17 from April 15 only applies to federal income tax returns. That deadline doesn’t always align with due dates for state income taxes.

Most states have followed the IRS and moved the deadline for income tax returns to May 17. But a handful of states still have different deadlines that impact millions of taxpayers.

Hawaii, Iowa, Maryland, and Oklahoma have state income tax deadlines that differ from the May 17 federal filing date. And, the deadline in Arizona could soon change.

Taxpayers in Hawaii have less time to prepare and file their state returns — the state deadline is April 30. In 2019, there were 1.1 million taxpayers in Hawaii, according to IRS data.

Others don’t have to file their state taxes until after the federal deadline. Maryland’s state Tax Day is July 15, and Oklahoma’s is June 15. That’s good news for Maryland’s nearly 5 million taxpayers and Oklahoma’s nearly 3 million, according to 2019 IRS data.

The nearly 2.5 million taxpayers in Iowa will also get more time. On Monday, the Iowa Department of Revenue extended the state filing deadline to June 1. Idaho also updated its tax day to match the federal deadline of May 17.

And, other states may still move their filing dates. The state income tax deadline is under review in Arizona, where the state legislature is considering a bill that would match the federal due date of May 17, according to the Arizona Department of Revenue.

Some taxpayers in a few other states have even more time to file both state and federal income taxes — those affected by severe winter storms in Texas, Oklahoma, and Louisiana have until June 15 to file their taxes, following disaster declarations issued by the Federal Emergency Management Agency.

What deadlines mean for taxpayers in those states

Taxpayers who live in states with earlier filing deadlines than federal Tax Day may not get to take advantage of the federal extension, said Ryan Losi, a CPA with Piascik based in Richmond, Virginia.

“A lot of states, their starting point is the federal AGI,” Losi said, referring to adjusted gross income calculated on an IRS Form 1040. That’s usually why federal returns are due before, or at the same time, as state returns, he added.

“To do the state [return] you’ve got to do your federal [return] anyway,” said Losi.

Of course, the states with earlier filing dates could still push back their deadlines to match or come after the May 17 federal Tax Day.

Still, taxpayers should keep these different deadlines in mind and work to prepare their returns sooner rather than later. Beyond the misaligned tax filing dates in some states, the IRS extension didn’t apply to quarterly estimated tax payments, generally made by those with self-employment income, interest, dividends, alimony or rental income. The first quarterly payment is still due April 15.