The due date for filing income tax return for corporate assessees and other assessees who are required to get their accounts audited under Income Tax Act 1961 or under any other law for the time being in force is 30th September and for others it is 31st July every year as have been prescribed u/s 139(1).
For a layman sometimes it may create doubt if he fails to file his return of Income within due date, whether he can file his return of Income after the due date, especially when he is under no obligation to get his accounts audited under Income Tax Act or under any other law.
The answer to this question is yes. Under section 139(4) a belated return can be filed as follows :-
For Assessment Year 2016-17 and Assessment Year Prior to A.Y 2016-17- at any time before before the expiry of one year from the end of relevant assessment year or before the completion of assessment whichever is earlier.
In other word a belated income tax return for FY 2015-16 (AY 2016-17) can be filed up to 31-03-2018 or before the completion of assessment whichever is earlier
For Assessment Year 2017-18 and after- at any time before the end of the relevant assessment year or before the completion of the assessment, whichever is earlier.
In other word a belated income tax return for FY 2016-17 (AY 2017-18) can be now filed only up to 31-03-2018 or before the completion of assessment whichever is earlier
But, where the assessee has some capital loss or loss from business or profession to be carried forward he should file his return of income within the due date as prescribed u/s 139(1). As per section 139(3), no loss shall be allowed to be carried forward under the head Business or Profession or under the head Capital Gain unless the return is filed within the due date as mentioned in section 139(1).
Where return of income is filed after the due date, interest u/s 234A will be payable. But if there is already tax has been deducted from the income of the assessee or advance tax has been paid by the assessee and there remains no tax to be paid after such T.D.S or advance tax then no interest is levied u/s 234A for filing the return after the due date.
It is to be noted that a penalty of Rs 5000 may be imposed u/s 271F if the return of income is not filed within the end of the relevant assessment year. For example, such penalty is imposable if return for asst. year 2011-12 is not filed by 31st March 2012.
It should also be noted that where a belated return is filed u/s 139(4), no revised return u/s 139(5) can be filed as it was held in Jagdish Chandra Sinha v. CIT 220 ITR 67 (SC).
Thus if your due date for filing return was 31st July and you miss to file it within due date you can still file it after the due date as stated above.