42-001: IA 1120 Iowa Corporation Income Tax Return 42-001 (2025)
Iowa · Iowa DOR · Used for tax years 2025
The 2025 IA 1120 is Iowa’s Corporation Income Tax Return. It reports federal taxable income, Iowa income adjustments and apportionment, tax, credits, and payments to calculate the balance due or overpayment.
What you'll need
Gather the following for your 2025 IA 1120:
- Your corporation’s legal name, address, Federal Employer Identification Number (FEIN), NAICS code, and tax period.
- A complete copy of your federal return as filed with the Internal Revenue Service. This must be filed with your Iowa return.
- Information from your prior-period Iowa return, including income before net operating loss.
- Records of estimated tax payments, credits from the prior period, voucher payments, and other payments.
- Iowa and everywhere receipts used to complete Schedule E.
Federal consolidated filers must include pages 1–5 of the consolidated federal return, consolidating income statements, federal Form 851 for status 3, Iowa Schedule H, and any other forms related to the Iowa return.
Include supporting forms and schedules when applicable, such as IA 148 for nonrefundable and refundable credits other than the fuel credit, IA 4136 for the fuel credit, Schedule CC for composite and PTET credits, and IA 2220 for the estimated tax underpayment penalty. Include a statement for other payments reported on Schedule C2, line 3.
How to file
You can e-file or mail your 2025 IA 1120. The printed mailing address is:
Corporation Tax Return Processing
Iowa Department of Revenue
PO Box 10468
Des Moines, IA 50306-0468
Include the required federal return copy and applicable supporting forms and schedules.
Sign the return by hand or use a digital signature with a digital certificate. Stamped or typed signatures are not accepted.
If you owe a balance, pay electronically or submit payment with a voucher. Forms and schedules are available at revenue.iowa.gov.
Common mistakes
- Do not use a stamped or typed signature. The form requires a handwritten signature or a digital signature with a digital certificate.
- Do not leave out the required federal return copy or the additional documents required for federal consolidated filers.
- Do not include estimated tax credit on page 2, line 15. That line is for credits from Schedule C1.
- Do not enter an amount below $0 on page 2, line 13.
- If annualizing tax, include a schedule showing the calculation.
- Include the required schedules for “Other” additions or reductions on Schedule A, and for partnership gross receipts or “Other” receipts on Schedule E.
Questions people ask
What tax rates does the 2025 form use?
If income on page 2, line 13 is $100,000 or less, multiply it by 5.5%. If it is over $100,000, multiply it by 7.1% and subtract $1,600.
Can an overpayment go toward the next period’s estimated tax?
Yes. Enter the overpayment on line 24 and the amount credited to the next period’s estimated tax on line 25. Subtract line 25 from line 24 to calculate the refund requested on line 26.
Can I use this form for an amended return?
The form has an “Amended Return” checkbox and lines 17a and 17b specifically for amended returns. Line 17a covers refunds and carryforwards and refers you to the instructions.
Where can I get forms or ask questions?
Forms and schedules are available at revenue.iowa.gov. The form lists 515-281-3114 and 800-367-3388 for questions, along with idr@iowa.gov.