Business Tax Deadlines

State filing information

Iowa

Business tax filing in Iowa: state returns, sales tax, other business taxes, and the federal dates that apply everywhere.

checked 2026-09-01Verified against Iowa Department of Revenue. 7 sources.

Corporate income tax return

April 30
Iowa corporation income tax return (IA 1120) is due on the last day of the fourth month after the end of the tax year...

Partnership / S corporation returns

April 30
Partnerships April 30; Same for S corporations

Sales tax return

Last day of the following month
sales and use tax · Effective July 1, 2022, quarterly filing was eliminated: taxpayers collecting less than $1,200 in sales and use tax per year file annually;...

Other business taxes

1 tax
Franchise tax (IA 1120F)

Iowa Department of Revenue

Other business taxes

TaxWho owes itDue
Franchise tax (IA 1120F)Financial institutions (banks, savings and loan associations, etc.) instead of corporation income tax

Rules in full

Corporate income tax

Iowa corporation income tax return (IA 1120) is due on the last day of the fourth month after the end of the tax year (cooperatives: 15th day of the ninth month).

Extension. Automatic six-month extension to file (no form required) for taxpayers who have paid 90% or more of the correct tax by the original due date;...

Partnerships and S corporations

S corporations (and partnerships) may make a Pass-Through Entity Tax (PTET) election to be taxed at the entity level; electing entities must make estimated payments; the PTET election must be made by the date six months after the original due date of the return (2025 IA 1120S instructions). Composite return (IA PTE-C) requirements apply to nonresident owners.

Sales and use tax

Due date. Monthly returns and payments are due on or before the last day of the month following the end of the month in which the tax was collected; annual returns are due on or before January 31 for the prior calendar year.

Filing frequency. Effective July 1, 2022, quarterly filing was eliminated: taxpayers collecting less than $1,200 in sales and use tax per year file annually; taxpayers collecting $1,200 or more per year file monthly. Deposit payments are no longer required.

Thresholds. Annual < $1,200 tax per year; monthly >= $1,200 per year.

Prepayments. None. Mandatory semimonthly deposits were eliminated effective July 1, 2022; payment is due only when a return is filed.

Notes

Iowa has no franchise, net worth, or gross receipts tax on general businesses and no LLC fee at the Department of Revenue. Iowa returns use the last day of the 4th month (April 30), not the 15th.

What we could not confirm. The IA 1065 partnership due date was not directly fetched (the corporation and S corporation instructions were); the same last-day-of-4th-month rule is assumed. Iowa DOR HTML landing pages for corporation income tax and PTET returned 404 at the guessed URLs, so corporate facts rest on two official instruction PDFs. Franchise tax (IA 1120F) due date not confirmed.

Federal dates that apply in Iowa

  1. SEP15Tue
    Individuals & Sole Proprietors
    Q3 2026 estimated tax payment (Form 1040-ES)
  2. SEP15Tue
    Partnerships
    Form 1065 extended return (Form 7004), tax year 2025
  3. SEP15Tue
    S-Corporations
    Form 1120-S extended return (Form 7004), tax year 2025
  4. SEP15Tue
    C-Corporations
    Q3 2026 corporate estimated tax (Form 1120-W)
  5. OCT15Thu
    Individuals & Sole Proprietors
    Form 1040 extended return (Form 4868), tax year 2025
  6. OCT15Thu
    C-Corporations
    Form 1120 extended return (Form 7004), tax year 2025

All 2026 federal deadlines

Sources

  1. https://revenue.iowa.gov/ official
  2. https://revenue.iowa.gov/taxes/file-my-taxes/business-taxes/filing-frequency-return-due-dates official
  3. https://revenue.iowa.gov/media/4083/download?inline= official
  4. https://revenue.iowa.gov/media/4373/download?inline= official
  5. https://revenue.iowa.gov/taxes/tax-guidance/sales-use-excise-tax/sales-and-use-tax-permit-return-filing-and-payment-changes official
  6. https://www.law.cornell.edu/regulations/iowa/Iowa-Code-r-701-202.1
  7. https://www.avalara.com/taxrates/en/state-rates/iowa/iowa-sales-tax-guide.html

Checked 2026-09-01; researcher confidence 0.85. Corrections with a link to the state's own page: contact@businesstaxdeadlines.com.