Calculate Ontario spousal support in minutes. Generate a courtroom-ready report.Use this free calculator to calculate spousal support according to the Canadian Spousal Support Advisory Guidelines, as well as child support (if applicable). You should keep in mind that this free online calculator only considers employment income and can only do simple calculations. Couples and the courts can use NYS spousal maintenance calculators to decide on the amount to be paid. There are two basic formulas used to calculate alimony in Ontario: the Without Child Support formula and the With Child Support formula. See how parenting time affects the total. Calculate spousal support (alimony) for FREE in less than five minutes, for any Canadian province. Includes tax and setoffs. A support or F petition is filed when a parent, guardian, spouse, or other relative wants child support from a non-custodial parent.