Use this free calculator to calculate spousal support according to the Canadian Spousal Support Advisory Guidelines, as well as child support (if applicable). Calculate Ontario spousal support in minutes.Generate a courtroom-ready report. You should keep in mind that this free online calculator only considers employment income and can only do simple calculations. To determine how much spousal support is required, calculate your gross income. This is the amount of money you make after taxes and other deductions. There are two basic formulas used to calculate alimony in Ontario: the Without Child Support formula and the With Child Support formula. Complete the fields below and press calculate to estimate alimony. The figures presented are based on legal California alimony guidelines. The court applies the California Guideline Child Support Calculator to determine the amount ordered to be paid for child support.