What you can do if you cannot pay your balance owing? Even if you cannot pay all of your balance owing right away, file your return by the filing due date. So you can avoid a late-filing penalty. If you cannot pay your balance owing on or before April 30, 2018, we may accept a payment
Interest If you have a balance owing for 2017, the Canada Revenue Agency charges compound daily interest starting May 1, 2018, on any unpaid amounts owing for 2017. This includes any balance owing if we reassess your return. In addition, the CRA will charge you interest on the penalties starting the day after your return is due.