If you owe tax for 2011 and do not file your return for 2011 on or before April, 30 2012, then the CRA may impose penalties and interest. They will charge you a late-filing penalty. The penalty is 5% of your 2011 balance owing, plus 1% of your balance owing for each full month that your return is late, to a maximum of 12 months. Your late-filing penalty may be higher if you were charged a late filing penalty in any of three previous years. We strongly suggest that, even if you can not pay the entire amount on April 30, that you still file to avoid the late filing penalty.