After the tax is due, how many days after will interest be applied?

In Washington, the application of interest on overdue taxes begins after a grace period following the due date of the tax. This grace period is specifically set at 61 days. Therefore, if the tax remains unpaid after this time, interest will start to accrue. Understanding this timeline is crucial for tax compliance, as any overdue taxes can lead to additional financial liabilities due to the interest applied.

In this context, recognizing the significance of the 61-day period is necessary for effective tax planning and helps ensure timely payments to avoid these accruing interest charges.