It’s important that we track multiple income streams properly to ensure we don’t end up with a large bill at tax time. Use a spreadsheet that includes these categories: Employer, Gross Income, Income Tax, CPP, EI, and Net Income (for each income stream). Total all streams so that you can calculate the total earnings, tax, CPP, and EI deducted so far. Then determine what the actual deductions should be, based on the combined income. The Canada Revenue Agency has an online calculator that is useful for this (http://www.cra-arc.gc.ca/esrvc-srvce/tx/bsnss/pdoc-eng.html). A qualified accountant can also help with any questions you might have.