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Penalty and interest
For Oregon corporation excise or income taxes
To avoid penalty and interest, you must pay any tax owed by the original due date of the tax return. You must also mail your tax return by the original due date, or by the extended due date if you file with a valid extension attached.

Conveniently pay tax, penalties, and interest using Revenue Online. Or use Form 20-V (Oregon Corporation tax payment voucher) to mail tax, penalties, and interest payments if mailed separate from your tax return.

Log in to Revenue Online

Penalties may include

  • 5 percent late pay (failure-to-pay) penalty on tax not paid by the original due date, even if there's a valid extension. More time to file doesn't mean more time to pay.
Exception: If you have an extension, penalty won't be charged if you:
  • Pay at least 90 percent of the tax due by the original due date of the return; and
  • Pay the balance of the tax when you file within the extension period; and
  • Pay any interest due when you file or within 30 days from our billing notice.
  • 20 percent late filing (failure-to-file) penalty on tax not paid in full by the original due date and the return is filed more than three months after the original or extended due date. This is in addition to the five percent failure-to-pay penalty.
  • 20 percent substantial understatement of income (SUI) penalty on tax attributable to certain adjustments to your return, totaling more than $25,000 for C corporations and $15,000 for other entities. This penalty is in addition to all other penalties
  • 100 percent late payment and late filing penalty on tax if you do not file returns for three consecutives years by the original or extended return filing due date of the third year.
The total of most penalties cannot be more than 100 percent of the tax due. Exception: the SUI penalty may be in addition to all other penalties.


You must pay interest on unpaid taxes if you don't pay the tax balance by the original filing due date. Interest owed on tax starts the day after the due date of your original return and ends on the date of your payment. Even if you get an extension to file, you still owe interest if you pay after the return’s original due date.

If you file an amended return and have tax to pay, we will charge interest starting the day after the due date of the original return until the date you pay in full.

If your taxable income is changed because of a federal or state audit and you owe more tax, we will charge interest from the due date of the original return to the date you pay in full.

An interest period is each full month, starting with the day after the due date of the original return. For example, April 16 through May 15 is one full interest period.

Interest is figured daily for a fraction of a month, based on a 365-day year.

To calculate interest:
Tax × annual interest rate × number of full years.
Tax × monthly interest rate × number of months.
Tax × daily interest rate × number of days.

Interest rates may change once a calendar year and are the same for refunds and tax due:
 For periods
 Annually  Monthly  Daily
​January 1, 2015 ​4% ​0.333% 0.0110%
​January 1, 2014 4%​ 0.333%​ 0.0110%
January 1, 2013 4% 0.333%  ​0.0110%
January 1, 2012  5%  0.4167%  0.0137%
January 1, 2011  5%  0.4167%  0.0137%
January 1, 2010  5%  0.4167%  0.0137%
Note: interest accrues on any unpaid tax during an extension of time to file.
Additional interest:
Interest will increase by one-third of 1 percent per month (4 percent yearly) on delinquencies if:
  • You file a return showing tax due, or the Department of Revenue has assessed an existing deficiency; and
  • The assessment is not paid within 60 days after the notice of assessment is issued; and
  • You have not filed a timely appeal.