Tax Day 2018 has come and gone, and hopefully your tax return was safely transmitted to the IRS by the deadline. 

Unfortunately, not everyone is able to file their taxes on time. If you've missed the tax deadline for the 2017 tax year, it's important to understand what to do next to minimize potential penalties or complications. 

The steps you'll need to take to resolve issue with your un-filed tax return will vary depending on whether you're getting a refund or if you owe. Read on to find your best course of action once tax day has passed without your tax return being filed. 

1040 Tax Form and Tax Refund

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If you're owed a refund

If you're owed a refund and you've been late with filing your tax return, you have nothing to worry about. You won't get hit with any penalties, and you still have plenty of time to file your taxes to claim your refund. In fact, you have until April 2021, as the IRS gives you three full years to claim an unclaimed refund. 

While you've got years left on the clock, you don't want to procrastinate too much, as the IRS will only accept e-filed returns for the 2017 tax year through November 2018. If you let that deadline pass, you'll have no choice but to submit a paper return. 

Waiting too long to file could also result in the IRS filing a substitute return for you. The substitute return might not include all of your deductions and credits, so it could show that you owe tax when should be due a refund. If this happens, you'd have just 90 days to take action if you didn't want the IRS to process the substitute return as if you'd submitted it. 

Bottom line: You're not in trouble, and you don't owe, but file your tax return and claim your refund before your situation gets more complicated, or before too much time passes and you lose your money forever. There are online programs that make filing easy and that may even allow you to file for free.

If you owe taxes

If you owe taxes, you need to file your late return right away. Failure to file when you owe taxes has much more serious penalties than failure to pay on time. In fact, the penalty for failure to file a tax return is 10 times greater than the penalty for paying late.

If you failed to file a tax return at all, you'll pay a penalty for each month (or part of a month) you're late. The penalty equals 5% of the unpaid balance on your taxes, with a maximum penalty of 25% of the unpaid tax balance. If you've failed to file and missed the deadline by more than 60 days, your minimum penalty is the lesser of 100% of the unpaid taxes you owe or $205. 

You can file a tax return even if you can't pay what you owe, although you should pay as much as possible to minimize penalties and interest.

Penalties for failure to pay on time equal 0.5% of the unpaid tax balance for each month (or part of a month) you're late, up to a maximum penalty equal to 25% of unpaid taxes. The smaller the amount of unpaid taxes, the smaller your penalty will be. 

You may also be able to work out a payment plan with the iRS. For short-term plans that give up to a maximum of 120 days to repay, you don't have to pay a fee to set up the payment plan. If you'll need more than 120 days, you can set up an installment agreement.

The fee for an installment plan is $31 to set up if you apply online and have payments made through automatic withdrawals. Applying via phone, mail, or in person raises the setup cost for this plan to $107 with auto-pay.

If you don't set up automatic payments but enter into an IRS installment plan, the cost to set up your plan is $149 for online applications or $225 if set up your plan via phone, mail, or in person. 

Minimum monthly payments for installment agreements are established by the IRS based on the unpaid tax balance you owe, including interest and fees.

Don't wait to act

Whether you owe taxes or are owed a refund, waiting longer to deal with your tax situation is only going to make things more complicated -- and potentially more costly. File your return today if you've missed the deadline so you can make things right with the IRS before they decide to reach out to you.