Iowa tax deadlines in 2026: filing dates and estimated payments
Deadlines that fall in calendar 2026: the 2025 return and the 2026 estimated payments. Different year? See Iowa 2025 →
Iowa deadlines in 2026
| 2025 individual return due | April 30, 2026 |
|---|---|
| Extended filing deadline | October 31, 2026 |
| Payment due | April 30, 2026, extension or not |
| Final 2025 estimated payment | January 31, 2026 |
| 2026 estimated payments | April 30, 2026 · June 30, 2026 · September 30, 2026 · January 31, 2027 |
Individual returns are due April 30 (not April 15). Automatic extension to October 31 if at least 90% of tax is paid by April 30. Estimated installments fall at quarter-end: April 30, June 30, September 30, January 31.
Iowa estimated tax payments in 2026
Every individual or married couple filing jointly that expects a tax liability of $1,000 or more from income not subject to withholding (threshold raised from $200 to $1,000 for tax years beginning on or after January 1, 2026).
| Q1 (2026 tax year) | April 30, 2026 |
|---|---|
| Q2 (2026 tax year) | June 30, 2026 |
| Q3 (2026 tax year) | September 30, 2026 |
| Q4 (2026 tax year) | January 31, 2027 |
| Voucher | Form IA 1040ES |
| Underpayment safe harbor | Pay 100% of the prior-year Iowa tax (110% if prior-year federal AGI plus Iowa decoupling adjustments exceeded $150,000, or $75,000 married filing separately), or at least 90% of the current-year tax on annualized income (Form IA 2210). |
| Pay online | govconnect.iowa.gov |
Iowa uses month-end dates. The state prints 01/31/2027 for the fourth installment; when a due date falls on a weekend the payment is due the next business day. The threshold rose from $200 to $1,000 for tax years beginning on or after January 1, 2026. Farmers and fishers may pay all by January 15, 2027 and file by April 30, or file and pay in full by March 1, 2027.
Source: revenue.iowa.gov, read September 3, 2026. “Installment 1 04/30/2026 Installment 2 06/30/2026 Installment 3 09/30/2026 Installment 4 01/31/2027”
All 51 jurisdictions in one table: state estimated tax payment dates for 2026.
Iowa extensions
Every state's rule in one table: which states accept the federal extension in 2026.
| Does Iowa accept the federal extension? | Not the federal one. The state extension is automatic when the required payment is made by the original due date. |
|---|---|
| Original due date | April 30, 2026 |
| Extended due date | October 31, 2026 |
| Payment | Still due April 30, 2026. The extension is to file, not to pay. If 90% of the correct tax is not paid by the due date, penalty and interest apply; interest accrues on any tax unpaid after the original due date. |
| How to get it | Nothing to file; pay at least 90% of the tax by April 30 (Iowa Individual Income Tax Payment Voucher 96-048 or online) and you automatically have until October 31 to file. |
October 31, 2026 is a Saturday; Iowa's FAQ states weekend due dates move to the next business day, so the effective date should be Monday November 2, 2026. The federal Form 4868 plays no role.
Source: revenue.iowa.gov, read September 3, 2026. “Iowa has no paper extension form. If you have at least 90% of the tax paid by the due date, you will automatically have until October 31 to file the return.”
Federal deadlines in 2026
| 2025 Form 1040 | April 15, 2026 · extension October 15, 2026 |
|---|---|
| 2025 S-corp (1120-S) & partnership (1065) | March 16, 2026 |
| 2025 C-corp (Form 1120) | April 15, 2026 |
| 2026 federal estimated payments (1040-ES) | April 15, 2026 · June 15, 2026 · September 15, 2026 · January 15, 2027 |
Source: IRS Publication 509 and Form 1040-ES instructions, irs.gov.
Frequently asked questions
When are Iowa state taxes due in 2026?
Your 2025 Iowa individual income tax return is due April 30, 2026. If that date falls on a weekend or legal holiday, the deadline moves to the next business day. An extension moves the filing deadline to October 31, 2026, but any tax owed is still due on the original date.
When are Iowa estimated tax payments due in 2026?
Iowa estimated payments for the 2026 tax year are due April 30, 2026, June 30, 2026, September 30, 2026, January 31, 2027. Use Form IA 1040ES or pay online. The final installment for 2025 was due January 31, 2026.
Does Iowa accept the federal extension?
Not the federal one. The state extension is automatic when the required payment is made by the original due date. The extended filing deadline is October 31, 2026, and tax is still due by April 30, 2026.
Does a Iowa extension give me more time to pay?
No. An extension extends the time to file, not to pay. To avoid penalties and interest, pay what you expect to owe by April 30, 2026.
Dates are the statutory deadlines that fall in 2026 and move to the next business day when they land on a weekend or holiday. Each section links to the source it was checked against. Always confirm with the Iowa tax agency or the IRS before relying on a date. This is general information, not tax advice.