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. Complete the fields below and press calculate to estimate alimony. The figures presented are based on legal California alimony guidelines. See how parenting time affects the total. This California alimony calculator calculates California maintenance using the California county alimony formulas. Maintenance, or spousal support, is crucial when major life changes occur within family dynamics. Use our California maintenance calculator. 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.