The Canada Revenue Agency regularly publishes a document called “Payroll Deductions Formulas,” which provides all the necessary calculations for payroll deductions collected by the CRA. For small business owners who prefer to handle their own payroll rather than using an external provider, these formulas can be implemented in a spreadsheet. However, the complexity of the tax system keeps increasing, and this year’s addition of “second additional premiums” to the Canada Pension Plan required a complete rewrite of the spreadsheet. Additionally, the authors of the document have overlooked a crucial software principle – calculating values before using them. To keep track of everything, the author created a dependency chart using GraphViz, which consists of 79 nodes showing the sequence of calculations. This chart does not include specific formulas but rather shows the dependencies between values. It simplifies the process and prevents circular calculations. The chart assumes that there are no commissioned employees, employees entering or exiting the Canada Pension Plan, or residents of Quebec, Nova Scotia, Yukon, or Ontario, each of which has its own unique tax complexities.
https://www.daemonology.net/blog/2023-12-31-Canadian-payroll-dependency-chart.html