IRS Notice CP30: Estimated Tax Penalty

What does an IRS CP30 notice mean?

A CP30 notifies you that the IRS reduced your refund or assessed a charge because you owe an estimated tax penalty — the penalty for underpaying tax throughout the year through withholding or quarterly estimated payments. The notice shows how the penalty was calculated.

Why did you receive a CP30?

Your withholding and estimated payments did not cover enough of your tax liability during the year, which commonly affects self-employed taxpayers, investors, and those with income not subject to withholding.

How to respond to a CP30 notice

If the penalty is correct, no further action is needed beyond accepting the reduced refund or paying any balance. You may qualify for a waiver if the underpayment resulted from a casualty, disaster, or other unusual circumstance, or if you retired or became disabled — request it with an explanation. To avoid it next year, increase withholding or make timely estimated payments.

What happens if you ignore it?

If the notice reduced your refund, the matter is generally closed; if it created a balance, penalties and interest accrue and collection follows.

Common resolutions

• Pay the penalty
• Request a waiver
• Adjust future withholding

Related IRS notices

• CP23 — Estimated Tax Payment Discrepancy
• CP215 — Penalty Charged — Failure to Pay Estimated Tax (Business)