Due Dates of Filling

Assessee Type	Due Date
A company	30-Sep-YYYY e.g. for financial year 2012-2013 i.e., 01-Apr-2012 to 31-Mar-2013, the due date is 30-Sep-2013
A person other than a company whose accounts are required to be audited under the Income Tax Act or any other law
A working partner of a firm whose accounts are required to be audited under the Income Tax Act or any other law
Any other taxpayer	31-Jul-YYYY

Note: If the last day for filing returns is a day on which the income tax office is closed,you can file the return on the next day afterwards on which the income tax office is open and, in such cases, the return will be considered to have been filed within the specified time limit/ due date.

Income tax returns can be filed after the due date upto end of assessment year (e.g. for FY 2011-2012, last date is upto 31-March-2013)

How to fill after due date?

Filing income tax returns after the due date is no different than filing it before the due date. The process and guidelines remains exactly the same. You can prepare and file your tax returns online or off-line (using paper returns).

Impact of Late Filling

Interest: You will be liable for penal Interest u/s 234A @ 1% per month on the amount of tax due from the due date of filing returns.
Carry Forward of Losses: Losses like Business Loss (speculative or otherwise), Capital Loss (short term or long term), and Loss from owning and maintaining race horses are not allowed to be carried forward. Other losses, if any can be carried forward.
Deductions: Deductions u/s 10A, 10B, 80-IA, 80-IAB, 80-IB and 80-IC are not allowed
Revision: Late returns cannot be revised except if it is in pursuance of a notice under section 142(1)
Penalty: A penalty of Rs.5000 may be imposed u/s 271F if belated return is submitted after the end of assessment year (after 31-March-YYYY, e.g. for FY 2011-2012, end of assessment year is 31-March-2013)

Due Dates of Filling