The Tax Filing Deadline Was Delayed to May 17. Here’s What to Know.

“They hear Tax Day is moved to May 17, so a lot of people will go to their preparer on April 30,” Mr. Stewart said. “Unfortunately, the first-quarter estimated payment is late.”

The conference and other groups representing tax professionals had urged the government to postpone the estimated tax deadline as well. In congressional committee testimony in March, the I.R.S. commissioner, Charles P. Rettig, said the estimated tax deadline hadn’t been changed because it would, in effect, be giving “a break” on interest and penalties to wealthy people, who would invest the money instead of paying the government.

But people who file estimated taxes also include sole proprietors and workers in the gig economy with modest incomes, accountants say. Many people who lost jobs in the pandemic switched to work delivering meals and groceries ordered by mobile apps, said Melanie Lauridsen, senior manager for tax policy and advocacy at the American Institute of Certified Public Accountants.

“That’s where the need is,” Ms. Lauridsen said.

The disconnect between the filing and estimated tax deadlines means tax preparers are pushed to get returns done by the traditional deadline anyway. “It’s putting a tremendous amount of stress on tax preparers,” said Rhonda Collins, director of tax content and government relations with the National Association of Tax Professionals.

In general, filers must estimate what they owe and round up to reduce the risk of underpaying. “It feels like it’s very much a guesstimate,” Ms. Collins said.

Should you incur a penalty when you file your tax return next year, you can request an abatement. Often, the I.R.S. is lenient with first-time errors, she said, especially when there are extenuating circumstances.

It’s also important to keep track of your income in 2021, tax professionals say. Many people had lower incomes than usual during 2020 because of the pandemic, and could see them rise in 2021 if the pandemic wanes as expected and the economy expands. If your income is turning out to be higher than expected, you may need to increase the amounts of your estimated payments later in the year.