(NewsNation) — Taxes are due Apr. 18, and if you’re feeling like you might not get it done in time, you might be considering filing an extension.

There are a few things you need to know first.

There’s a myth that if you file an extension, you don’t have to pay what you owe right away. That isn’t the case. You still owe the money by the regular tax deadline, you’re just getting an extension to officially file your return.

You have to estimate what you owe the government and still pay it come Apr. 18, regardless of whether your paperwork is complete.

That’s if you owe the IRS money, of course. For those getting a refund, it’s a little different. Here’s a breakdown.

If you owe, you’re expected to pay most of your bill up front, preferably 90% of it, on Apr. 18. Anything you owe after the deadline could get interest and late fees tacked on, on top of the original amount. A tax professional can be an excellent resource on estimating what you should be paying come tax day.

If you’re getting a refund, filing for an extension doesn’t really penalize you — it’s simply giving you more time to get your documents in order. It also protects you if you actually do end up owing the government.

Of course, things happen, and extensions are meant to give taxpayers a bit of wiggle room. Many Americans were impacted by natural disasters in the past year, so, in this case, the IRS might be willing to give you more time to file.

There are a few ways to file an extension. You’ll need to submit Form 4868 by Apr. 18, electronically or by mail. You can file with IRS partner Free File Alliance, and most tax websites also offer an extension option. As always, a tax professional can also file the form on your behalf.

Filing an extension gets you six more months, making your new tax deadline Oct. 16.