This calculator is for statewide use. Illinois Alimony Calculation.Illinois uses a formula that considers both spouses' incomes and the length of the marriage. Illinois has established a specific formula for calculating the amount and duration of spousal maintenance obligations or awards. The calculator below can provide you with an estimate as to how a court may handle alimony. This Illinois alimony calculator makes Illinois maintenance calculations using the Illinois alimony formula. Use our FREE online Arizona alimony calculator to determine spousal maintenance costs in AZ. âś“ Instant. Under the Maricopa County formula, the maintenance amount is equal to the payor spouse's income minus the recipient spouse's income. Under the Maricopa County formula, the maintenance amount is equal to the payor spouse's income minus the recipient spouse's income. How do you fill it out and why do you need to complete one?