Calculating Debt Payoff. If you have unpaid child support debt, you can figure out how long it will take to pay it off with our Arrears Payoff Calculator.The Payment Estimator applies the statewide uniform guideline calculation to the information that you enter into the blank fields. See how parenting time affects the total. Complete the fields below and press calculate to estimate alimony. The figures presented are based on legal California alimony guidelines. We provide a calculation printout that can be used to help formulate sums for child support, temporary spousal support while the divorce case is active. To estimate the amount of child support that may be ordered in your case, you can use the state's official Child Support Guideline Calculator. The Family Courts will generally order Child Support based upon an algebraic formula that takes into account the incomes of both parents. A comprehensive overview of spousal support in California, covering types, factors, modifications, and legal implications involved.