If you did not pay enough tax during the year either through withholding or by making estimated tax payments, you may have to pay a penalty. In certain situations, you will not have to pay the penalty, such as if you had no tax liability in the prior year or if your current-year tax minus withholding is $1,000 or less.

If a taxpayer did not pay enough tax on a timely basis during the year, he or she will have an underpayment of estimated tax, and may, depending on circumstances, be required to pay a penalty. The penalty, if any, is computed on Form 2210.

A penalty for not paying enough total estimated tax and withholding. To avoid underpayment penalties, you can pay a percentage of last year's tax due or of the current year's expected tax due. The taxes may be paid in the form of combined estimated and withholding tax payments.

A penalty for not paying enough total estimated tax and withholding. You can avoid underpayment penalties by paying a percentage amount of last year's tax due or of the current year's expected tax due. You may pay the taxes in combined estimated and withholding tax payments.

A tax penalty enacted on an individual for not paying enough of his or her total estimated tax and withholding. If an individual has an underpayment of estimated tax, they may be required to pay a penalty (on Form 2210).