Tax due dates

The date your taxes are due depends on your reporting status. Your reporting status indicates how often you are required to file taxes and is listed on your business license. You can also find it online by accessing your SELF account. If you do not know your reporting status, contact us.

This table summarizes Seattle business license tax due dates for each reporting status:

Reporting StatusTax return due date
Annually:
     calendar year ends Dec. 31 Jan. 31
Quarterly:  
     1st quarter ends March 31 April 30
     2nd quarter ends June 30 July 31
     3rd quarter ends Sept. 30 Oct. 31
     4th quarter ends Dec. 31 Jan. 31
Monthly:  
     March 31, for example Last day of following month:
April 30, for example

Late fees and interest

You pay a penalty fee for filing taxes after the due date. The penalty fee increases the longer you wait to file.

Tax return filedLate fee amount
1st month after the due date 5% of tax owed
2nd month after the due date 15% of tax owed
3rd month after the due date,
or anytime after
25% of tax owed
  ($5 minimum penalty)


In addition to late fees, you must also pay interest if you file late. Interest accrues from the due date until the date paid. The interest due is equal to:

(interest rate / 360) x (tax owed amount) x (number of days late)

You will not be charged a late fee or interest if you do not owe any tax. But you must still file a tax return.