An assessee who files his return by the due date' (normally July 31) is allowed to file a revised return, in case he discovers some omissions or other incorrect details, even like wrong PAN number, wrong bank details etc.
Time limit for filing revised return is one year from the end of the assessment year or before completion of assessment. No penalty would be levied for filing a revised return on voluntary basis.
So, the question now arises is does one lose the revision option, if one files the returns late? Yes. If an assessee does not file his return within the due date' and files his return subsequently, he cannot have the benefit of revising the return, as the return filed beyond the due date' is treated as belated return'.
Another advantage of the taxpayer filing the tax returns on time is that he gets to carry forward and set off of losses, such as loss from business and loss under the head capital gains'. If the return is filed beyond the due date', these losses cannot be carried and set off against the income of subsequent years.
Yet another advantage of filing return before due date' is the eligibility for interest on tax refund from April 1 of the assessment year.
This also means where the return is filed after the due date', interest on refund is paid only for the period from the month of filing the return to the date of refund. In other words, no interest is paid for the period from April 1 of the assessment year to the date of filing the belated return'.
Apart from this late filing will attract interest and penal interest.