45-006: IA 2220 Underpayment of Estimated Tax 45-006 (2025)
Iowa · Iowa DOR · Used for tax years 2025
The 2025 Iowa IA 2220 determines whether estimated tax was paid in the correct amounts by the required dates and calculates any underpayment penalty. It includes calculations for quarterly underpayments and exceptions that may avoid a penalty, and must be included with the applic
Who files this form
The 2025 IA 2220 is used by:
- Corporations and financial institutions.
- S corporations that owe built-in gains/passive investment tax or make a Pass-Through Entity Tax (PTET) election.
- Partnerships that make a PTET election.
It determines whether estimated tax was paid in the correct amounts and on time, and whether an underpayment penalty applies. Taxpayers with more than $1,000 in tax due after credits must pay estimated tax.
Include IA 2220 with your return even if no underpayment penalty is due.
When it's due
For tax year 2025, estimated tax installment dates are the last day of the 4th, 6th, 9th, and 12th months of your taxable year. Enter these dates on line 4 and use the same dates on line 13.
What you'll need
Have these records available to complete the form:
- Your business name, Federal Employer Identification Number (FEIN), and tax period.
- Your 2025 Iowa return: IA 1120, IA 1120F, IA 1120S, or IA 1065, for the tax and credit amounts used on lines 1 and 2.
- Records of estimated tax payments, amounts credited, and payment dates.
- Your prior-year return if you use Exception 1, or prior-year income information if you use Exception 2.
If you use Exception 3 for annualized income, include a schedule and enclose income statements for the appropriate months in the tax period.
How to file
Include the completed IA 2220 with your Iowa return: IA 1120, IA 1120S, IA 1120F, or IA 1065, even if no penalty is due.
If you calculate a penalty on line 19, also enter it on the applicable return:
- IA 1120, line 20.
- IA 1120F, line 19.
- IA 1120S, line 49.
- IA 1065, line 40.
Common mistakes
- Leaving out IA 2220 because no penalty is due. The form must still be included with your return.
- Counting tax credits twice. Do not include tax credits on line 6(a), including Composite Tax Credits or PTET Credits received from a pass-through entity. These are already included on line 2.
- Using Exceptions 1 or 2 on an initial-year Iowa return. Neither exception is available to initial-year filers.
- Using Exception 1 without meeting its conditions. The prior tax year must cover 12 months, and a return showing a tax liability, including zero liability, must have been filed. Additional restrictions apply to partnerships and S corporations based on their prior-year PTET election or tax status.
- Completing lines 1 through 8 unnecessarily. If you qualify for exceptions that avoid the penalty for all quarters, skip those lines and go directly to line 9.
- Omitting annualized-income support. If you use Exception 3, include the schedule and income statements for the appropriate months.
Questions people ask
Can an exception prevent an underpayment penalty?
Yes. Payments must be made on or before the installment due date, and total payments by that date must equal or exceed the amount required under an applicable exception. Complete lines 9 through 12 to show the exception you rely on.
Can I use a different exception for each installment?
Yes. A different exception may be applied to each underpayment.
Can an extra installment payment cover an earlier underpayment?
Yes, but only the amount that exceeds the current installment amount computed on line 5 counts toward a previous underpayment.
When does the penalty calculation stop if I make a payment that covers an exception?
Once that payment is made, the underpayment is no longer outstanding, and the penalty calculation stops on the payment date.
Where can I ask questions?
Call 515-281-3114 or 800-367-3388, email idr@iowa.gov, or visit revenue.iowa.gov.