Iowa Business Tax Deadlines (2026)
Next: June 15, 2026 — Federal Q2 Estimated Tax Payment & Iowa Q2 Estimated Tax Payment (June 30)
Next Deadline: June 15, 2026 — Federal Q2 Estimated Tax Payment & Iowa Q2 Estimated Tax Payment (June 30)
Federal Tax Deadlines (2026)
| Form | Who Files | Due Date | Extension Deadline |
|---|---|---|---|
| Form 1040 (Schedule C) | Sole proprietors | April 15 | October 15 |
| Form 1065 | Partnerships, Multi-member LLCs | March 15 | September 15 |
| Form 1120-S | S-Corporations | March 15 | September 15 |
| Form 1120 | C-Corporations | April 15 | October 15 |
| Form 990 | Nonprofits | May 15 | November 15 |
| Estimated Taxes (Q1) | All | April 15 | — |
| Estimated Taxes (Q2) | All | June 15 | — |
| Estimated Taxes (Q3) | All | September 15 | — |
| Estimated Taxes (Q4) | All | January 15, 2027 | — |
Iowa State Tax Deadlines (2026)
| Tax Type | Due Date | Form/Filing | Notes |
|---|---|---|---|
| Individual Income Tax | April 30 | Form IA 1040 | Flat 3.8% rate; due April 30 |
| Corporate Income Tax | April 30 | Form IA 1120 | Graduated 5.5%–7.1% (transitioning) |
| S-Corp Return | March 31 | Form IA 1120S | Due last day of 3rd month |
| Partnership Return | March 31 | Form IA 1065 | Due last day of 3rd month |
| Sales Tax (Monthly) | 20th of following month | Via GovConnectIowa | State rate 6% |
| Withholding Tax (Monthly/Semi-monthly) | Varies by payroll | Via GovConnectIowa | Employers |
| Biennial Report | April 1 (odd years) / April 1 (even years vary) | Filed with Secretary of State | $30 (Corp); $60 biennial (LLC) |
| Estimated Income Tax (Q1) | April 30 | Form IA 1040-ES | Note: April 30 |
| Estimated Income Tax (Q2) | June 30 | Form IA 1040-ES | Note: June 30 |
| Estimated Income Tax (Q3) | September 30 | Form IA 1040-ES | Note: September 30 |
| Estimated Income Tax (Q4) | January 31, 2027 | Form IA 1040-ES | Note: January 31 |
Quarterly Estimated Tax Deadlines in Iowa
Iowa's estimated tax deadlines differ from the federal schedule — they fall on the last day of the month:
Estimated payments are required if you expect to owe $200 or more in Iowa income tax.
Iowa-Specific Tax Requirements
Iowa has been undergoing significant tax reform. The individual income tax has been reduced to a flat rate of 3.8% (down from a top rate of 8.53% in prior years). Corporate income tax rates are being reduced on a graduated schedule, with rates currently ranging from 5.5% to 7.1% depending on income level. Iowa's tax returns are due April 30 (not April 15), giving filers an extra two weeks beyond the federal deadline.
Iowa's state sales tax rate is 6% with an additional 1% local option sales tax in most jurisdictions, bringing the typical combined rate to 7%. The economic nexus threshold for remote sellers is $100,000 in sales. Iowa does not impose a franchise tax or gross receipts tax.
Iowa requires a biennial report filed with the Secretary of State. Corporations file biennially for $30, and LLCs file biennially for $60. Employers must register for withholding tax and can file monthly or semi-monthly. Iowa's tax reform has made the state significantly more competitive, especially with the move to a flat individual income tax rate.
What Happens If You Miss an Iowa Tax Deadline?
Iowa Department of Revenue
Get Your Books Ready Before Tax Season
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