If your employer is withholding money for income taxes from your check how do you end up owing the IRS.
Your employer withholds based on the information you provide on your W-4. I have had clients who have claimed up to 99 exemptions on their W-4s. This means that not enough money is being withheld and so you owe the IRS.
Another big problem area is retirement accounts. Many people don’t understand that tax deferred accounts are taxed as regular income when the money is distributed. On top of that up to 85% of your Social Security benefit can be taxable depending on your other income.