Here's what to do if you screwed up on your taxes

Tax season is starting to wind down. On Thursday, the IRS said it had received almost 93 million tax returns so far this season.

But what happens if you realize after you've filed your taxes that you've made a mistake? Or perhaps another tax document arrived in the mail after you submitted everything to the IRS?

It's OK. The IRS has dealt with this type of situation before and has potential solutions for you in place. Here are some helpful steps you can take if you're worried you've made a mistake.

"There's no need to panic," Laurie Kazenoff, a partner and co-chair of the tax department at Moritt Hock & Hamroff, tells CNBC Make It. Most small issues can be resolved fairly easily, she says.

For example, if the mistake you realize you've made has to do with math, it's no big deal: The IRS will catch and automatically fix simple addition or subtraction errors.

And if you forgot to send in a document, the IRS will usually reach out in writing to request it.

If the issue is a small one, the best thing you can do is wait until the IRS has fully processed your initial tax return. At that point, you will be able to see if the IRS simply corrected the error or has asked you to submit more information.

And Kazenoff says it's OK to cash the refund check from the original return before receiving any additional refund that may be due to you.

"You really should wait until that first return is processed because you want it to go through the system," says Kazenoff, who previously worked as a senior tax attorney with the Office of Chief Counsel at the IRS. "Better to wait for it to get processed." The IRS says that most returns are processed within 21 days.

If your error means you actually owe more to the IRS, the process can be a little more complicated. But for most people, it's still manageable. Read on for what to do if you have a bigger tax mistake to solve.

If you think you've made a bigger mistake — you need to change your filing status, correct your income, or change your deductions or credits, for example — then you're probably going to have to correct your taxes through an amended return process.

The IRS website offers an interactive tax questionnaire that walks you through the question, "Should I file an Amended Return?" The automated assistant asks various questions and, depending upon your answers, it will tell you whether or not you need to amend. You have three years to file an amended return.

If you used TurboTax to file your return, the software can also walk you through amending your tax return, Lisa Greene-Lewis, a TurboTax expert and CPA, tells CNBC Make It. She adds that if you prepared your taxes with TurboTax Live, you can connect with the TurboTax Live CPAs and enrolled agents year-round to get help amending your return.

But filing an amended return can also be done without help, especially if it's something fairly straightforward. For example, say you didn't include a 1099. That's typically easy to resolve, Kazenoff says. If you're missing a document, again, the IRS can handle this and typically alerts you by mail.

The situation can be different if you own a business, for example, and your issues pertain to more complex deductions or credits. In that case, you may want to seek expert assistance. "The more complicated the return is and the greater the dollars involved, having a tax professional who is well-versed in these areas is recommended," Kazenoff says.

Once you've followed those steps, here are a couple of other facts to keep in mind.

Note that the IRS doesn't accept amended returns electronically. You'll need to mail in a paper form to correct any errors.

"Taxpayers can't file amended returns electronically and should mail the Form 1040X to the address listed in the instructions," Kazenoff says.

The upside is that if the IRS catches the mistake first and you receive a letter or a notice about it, it may not be necessary to prepare an amended return, Kazenoff says. It's possible that discrepancies can be worked out with the IRS, she says. If you end up needing to pay more, you can simply agree with the notice and pay in response to the notice rather than amending.

"You can go back three years to amend your taxes if you think you left something out of previous years' tax returns," Greene-Lewis says. Keep in mind that if you need to correct mistakes going back multiple years, you'll have to use separate amended returns for each year. Each year should be done on a separate form and mailed in a separate envelope.

If you forgot to report income, such as that from a side hustle, Kazenoff says you'll likely need to file an amended return, and pay.

You should plan to pay the taxes on that unreported income before the April 15 due date. If you don't, you're going to owe interest on the outstanding balance. You may also face a late filing penalty.

You can file an extension, but keep in mind that doesn't extend the time to pay, Kazenoff says. You'll need to estimate what you owe and send it into the IRS before your filing deadline. And it's important that your estimate be as accurate as possible, she adds. This year, the IRS says you need to pay 80 percent of what you owe for the 2018 tax year to avoid a penalty.

Once you file an amended return, you can track its progress. Three weeks after mailing in your return, you can use the "Where's My Amended Return?" page on the IRS website. Processing can take up to 16 weeks.

Don't miss: Here's who is more likely to get a lower refund this tax season, according to experts

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