Ohio doesn't have a formula for calculating spousal support or even determining who's entitled to receive it. Illinois has established a specific formula for calculating the amount and duration of spousal maintenance obligations or awards.Calculate alimony quickly and accurately with our state-specific alimony calculators. Get an estimate based on your state's guidelines for free. Under this formula, 25 percent of the recipient's gross annual income is subtracted from 33â…“ percent of the paying spouse's gross annual income. Illinois uses a complex formula for calculating alimony. The Ohio Child Support Calculator will provide an estimate of the support obligations that may be included in a court or administrative child support order. Learn about the types of alimony available in Illinois, how it's calculated, and the factors courts consider when awarding spousal maintenance. The following calculator provides an estimate of a potential alimony award in the State of Ohio. MaritalLaws; Alimony Calculator.