(Daniel Acker/Bloomberg)

You put off doing your taxes, and the deadline is here. So you buckle down to get it done, only to discover you don’t have what you need to finish.

Or you aren’t sure how to factor in the fact that you lived in two states last year and worked in three. There’s a good chance you won’t pull it all together before midnight. Should you panic?

Not necessarily.

The good news is that it’s fairly easy to get more time to prepare your return. The bad news is that taxes are still due by midnight April 15. After that, the clock starts ticking for interest and penalty charges.

Some people who are expecting a tax refund may be tempted to file late. They technically have plenty of time  — until April 15, 2018 — to collect their 2014 tax refunds. (By the way, that also means you have until midnight tonight to file and cash in on your 2011 tax refund.)

But procrastinating much longer could be a huge gamble. For instance, what if it turns out that you actually owe money? A raise, a forgotten 1099 or a new tax rule could turn that refund into a tax bill, says Melissa Labant, a tax specialist at the American Institute of CPAs.

[The smartest tax move you can make today]

For every day that your tax return is late and your taxes go unpaid, the bill would grow with penalties and interest charges. In that case, dragging your feet on filing could be especially painful because the penalties for filing a late return are steeper than the fees for paying late.

Late filing penalties are usually 5 percent of the tax bill for each month (or part of a month) that a return is late, up to 25 percent of the tax bill. Late payment penalties typically amount to 0.5 percent of taxes owed for each month after April 15 that taxes are not in. For a $5,000 tax bill that is one month late, it’s a difference between $275 for filing late and paying late, and $25 for just paying late — and that’s not including interest.

To be safe, people who need more time to work on their returns should file form 4868 to get an automatic six-month extension, Labant says. You can quickly and easily e-file the form through the IRS site or most tax-preparation programs. You don’t even have to explain yourself. (That comes later.)

People who are in over their heads can try to book an accountant who can help estimate their taxes, file an extension and then sit down with them later to work on the return, she says. But good luck finding someone who’s taking appointments on the last day of the tax season.

Failing to file a return could have other consequences for people who bought health insurance on the public exchanges. As part of the Affordable Care Act, anyone who received a subsidy to help pay for insurance expenses is required to file a tax return to confirm that the tax credit they received is accurate.

Some people who may not have been required to file tax returns in the past may be confused by the change and could have a hard time signing up for new insurance policies when the next open enrollment period starts in the fall, according to a report released by H&R Block this week reminding people to file.

Read More:

What to do if you don’t have the money to pay your taxes

How to make the most of your tax refund

This is how much it will cost you to do your own taxes