Use this free calculator to calculate spousal support according to the Canadian Spousal Support Advisory Guidelines, as well as child support (if applicable). Use our calculator for Canadian spousal support estimates to help you understand what your support payments may look like.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. Our tool will calculate how much spousal support a judge may order. Complete the fields to calculate and estimate. She will not be expected to have provided for her old-age out of the considerable maintenance she has received.