The filing calendar is simple enough that confusion usually starts with wishful thinking
CRA's tax-season material gives the main dates plainly: most individuals file and pay by April 30, while self-employed individuals generally file by June 15 but still pay by April 30 to avoid interest. The common mistake is hearing the later filing deadline and mentally moving the payment deadline with it. CRA explicitly says not to do that.
The penalty formula is harsh enough that delay becomes expensive quickly
CRA's late-filing page says the standard penalty is 5% of the balance owing plus 1% for each full month late, up to 12 months. The repeated late-filing penalty is higher, and unpaid tax also attracts compound daily interest after the due date. In other words, the system punishes both lateness and non-payment rather than asking taxpayers to choose one problem or the other.
The safest practical rule is to separate filing discipline from cash-flow trouble
People in financial stress often freeze and delay the whole process. CRA's own guidance is pushing in the opposite direction: file the return on time, then deal with the balance. That is not a magic cure, but it can stop a cash shortfall from becoming a larger compliance failure as well.
Educational content only
This guide is for general education, not personalized tax advice. Tax rules change and your facts matter — confirm anything important with a qualified professional or the cited official source before taking action.