What's different for self-employed people in Canada
You pay both halves of CPP
Employees and employers each pay CPP. When you're self-employed you pay both: 11.9% on most earnings, plus CPP2 on earnings between the first and second ceilings. It's often a bigger bill than federal income tax at middle incomes.
Tax may be due in instalments
With no employer withholding tax, you may need to pay quarterly instalments on March 15, June 15, September 15 and December 15. See CRA required tax instalments.
GST/HST once you pass $30,000
Most freelancers must register for GST/HST once taxable sales go over $30,000 in a calendar quarter or four consecutive quarters, and then charge the rate for where their client is.
Filing deadline vs payment deadline
Self-employed people have until June 15 to file, but any balance owing is still due by April 30.
Tip: the CRA's sole proprietorships and partnerships pages are the best free starting point for Canadian rules.