What is the interest charged on a delinquent payment calculated from?

The interest charged on a delinquent payment is calculated from the original due date of the return to the date paid. This is because the tax law specifies that interest on unpaid taxes accrues starting from the date the payment was originally due. The rationale behind this approach is to ensure that taxpayers are incentivized to pay on time; if they do not, they become liable for interest from the moment the payment was expected.

Choosing this calculation method aligns with standard practices in tax collection, where the timeline for accruing interest begins at the established due date rather than from other potential starting points like the last payment date or the date of a billing notice. This consistent starting point helps maintain clarity and fairness in the collection of tax obligations.