Pacific · WA
How to file Washington sales tax
2026 due dates, filing frequencies, form Combined Excise Tax Return, and official filing resources.
- State return: Combined Excise Tax Return
- Monthly returns due: 25th of the following month (combined excise return)
- Filing frequencies: Monthly, Quarterly, Annual
When is Washington sales tax due?
Monthly Washington sales tax returns are due the 25th of the following month (combined excise return). Quarterly returns are due the last day of the month following the period (Apr 30 / Jul 31 / Oct 31 / Jan 31). When a due date lands on a weekend or federal holiday it moves to the next business day; the 2026 calendar on this page already applies that adjustment.
Washington sales tax due dates for 2026
Every date below comes from the state's published deadline rule (dataset 2026.07.0) and is already moved to the next business day when it lands on a weekend or federal holiday. Your account's assigned filing frequency decides which table applies.
Monthly Washington sales tax due dates
Rule: 25th of the following month (combined excise return).
| Period | Period ends | Return due |
|---|---|---|
| January 2026 | Jan 31, 2026 | Feb 25, 2026 |
| February 2026 | Feb 28, 2026 | Mar 25, 2026 |
| March 2026 | Mar 31, 2026 | Apr 27, 2026 (moved: 2026-04-25 falls on a Saturday) |
| April 2026 | Apr 30, 2026 | May 26, 2026 (moved: 2026-05-25 is a federal holiday) |
| May 2026 | May 31, 2026 | Jun 25, 2026 |
| June 2026 | Jun 30, 2026 | Jul 27, 2026 (moved: 2026-07-25 falls on a Saturday) |
| July 2026 | Jul 31, 2026 | Aug 25, 2026 |
| August 2026 | Aug 31, 2026 | Sep 25, 2026 |
| September 2026 | Sep 30, 2026 | Oct 26, 2026 (moved: 2026-10-25 falls on a Sunday) |
| October 2026 | Oct 31, 2026 | Nov 25, 2026 |
| November 2026 | Nov 30, 2026 | Dec 28, 2026 (moved: 2026-12-25 is a federal holiday) |
| December 2026 | Dec 31, 2026 | Jan 25, 2027 |
Quarterly Washington sales tax due dates
Rule: Last day of the month following the period (Apr 30 / Jul 31 / Oct 31 / Jan 31).
| Period | Period ends | Return due |
|---|---|---|
| Q1 2026 | Mar 31, 2026 | Apr 30, 2026 |
| Q2 2026 | Jun 30, 2026 | Jul 31, 2026 |
| Q3 2026 | Sep 30, 2026 | Nov 2, 2026 (moved: 2026-10-31 falls on a Saturday) |
| Q4 2026 | Dec 31, 2026 | Feb 1, 2027 (moved: 2027-01-31 falls on a Sunday) |
Annual Washington sales tax due dates
Rule: April 15 following the calendar year.
| Period | Period ends | Return due |
|---|---|---|
| Calendar year 2026 | Dec 31, 2026 | Apr 15, 2027 |
Washington filing notes
- ACH debit must complete by 11:59 p.m. PT on the due date; ACH credit funds must deposit by 5 p.m. PT.
Return and form
The principal repository-tracked return is Combined Excise Tax Return. Paper eligibility is taxpayer-specific; electronic filing or a waiver may control.
Tracked form version: December 2025 (file code CETR_25_12; "Internet/Fax (12/30/25)" revision line printed on each page)
Paper filing posture: taxpayer specific
Official Washington filing resources
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Workflow support does not by itself establish registration, filing authority, credentials, agency acceptance, or tax advice. Confirm your assigned filing frequency with the state.
Washington sales tax filing questions
When is Washington sales tax due?
Monthly Washington sales tax returns are due the 25th of the following month (combined excise return). Quarterly returns are due the last day of the month following the period (Apr 30 / Jul 31 / Oct 31 / Jan 31). When a due date lands on a weekend or federal holiday it moves to the next business day; the 2026 calendar on this page already applies that adjustment.
How often do you file sales tax in Washington?
Washington assigns a filing frequency to each account. The published cadences are monthly, quarterly and annual filing; the state assigns the frequency based on tax volume and notifies the account, so confirm the assigned basis before relying on a calendar.
What form is used to file Washington sales tax?
The Washington return tracked here is Combined Excise Tax Return. The principal repository-tracked return is Combined Excise Tax Return. Paper eligibility is taxpayer-specific; electronic filing or a waiver may control.
What happens if a Washington due date falls on a weekend or holiday?
The due date moves to the next business day. In 2026, 7 of the Washington due dates listed on this page are adjusted for a weekend or federal holiday; each adjusted date is marked in the calendar.
Can Washington sales tax be filed on paper?
Paper filing posture tracked for Washington: taxpayer specific. The principal repository-tracked return is Combined Excise Tax Return. Paper eligibility is taxpayer-specific; electronic filing or a waiver may control.