After doing your taxes, or having your taxes prepared by a professional, you’ll see that you either owe money to the IRS or that you’ll be getting a tax refund. If after your tax preparation you find that you do owe, but weren’t expecting it, this could be due to an error, changes in the tax code, changes in your income, and changes in your deduction options, along with a long list of other possibilities.

If you find that you owe more on your state or federal tax return than you thought you would, the first thing you should do is check to make sure your tax return is free of errors. For example, did you accidentally input the same income twice? Did you input an incorrect filing status? Or did you forget a deduction you normally claim? If you owe the IRS money but weren’t expecting to, it’s crucial to double check your return for these types of errors.

However, you might find that you owe the IRS money even with an error-free return. New life circumstances and changes in federal tax law can affect your tax liability. Things like inheriting money, marriage, divorce, a new job, new self-employment income taxes, and deaths can cause you to owe more money to the IRS at tax time.