IRS form used to calculate whether a taxpayer owes a penalty for underpaying estimated taxes
. Completing IRS Form 2210
helps you to figure out the amount of the penalty or to demonstrate to the IRS why you do not owe a penalty. Even if you are not required to file Form 2210, you can use it to determine any penalty that you may owe. In that situation, you enter the penalty on your tax return without filing Form 2210.