Jackson Hewitt Tax Practice Test

The key idea is that an underpayment penalty happens when you don’t pay enough of your tax during the year through withholding and timely estimated tax payments. If the total amount you’ve paid through withholding plus estimated payments falls short of your actual tax for the year, you may owe this penalty. The amount is determined using Form 2210 to see how much was underpaid and for how long.

Safe harbors help you avoid the penalty: if you’ve paid at least 90% of the current year’s tax or 100% (110% if your adjusted gross income is high) of last year’s tax through withholding and estimated payments, you generally won’t owe the penalty even if you end up owing at filing.

Filing late is a separate issue that can trigger late-filing penalties, not the underpayment penalty. Paying too much through withholding means you’ve overpaid, which doesn’t trigger an underpayment penalty. Earned income exceeding a threshold isn’t itself the triggering factor; the penalty depends on whether enough tax was paid during the year.