Which period shall be considered for interest under section 234B if self-assessment tax is not paid?
​​If the assessee did not pay the self-assessment tax, the interest shall be charged for the period commencing from April 1 of the assessment year and ending on the date of determination of income under Section 143(1) and where a regular assessment is made to the date of such regular assessment.

However, if the return is accepted as is filed by the assessee and no addition is made during the assessment, then interest shall be charged till the date of filing of the return by the assessee.​