Knowledge is Power: Calculate Your Illinois Child Support

Child Support Calculator

Estimate Your Illinois Child Support Obligations

When using the calculator, it is important to keep in mind that the estimate is based entirely upon the specific information provided. The exact circumstances of your case are unique, and many child support orders are customized to meet the needs of a particular situation. The calculator cannot reasonably account for the additional needs or resources of either parent or the child, or any other subjective considerations. Based on the results provided by the calculator, you may wish to speak with a qualified legal professional for guidance regarding your child support concerns.

Non-Custodial Parent’s income


Deductions from Gross Income


Gross Income From Employer

Gross income is the total amount of income paid to you by your employer. It is the amount before taxes, social security, pension and other benefits are taken out. It is not ​the amount you receive in your paycheck each pay period but rather the amount ​before​ deductions. If this amount does not include tips and/or bonuses, you will need to enter those numbers in the box called ​Other Income.

*​Please note: you may use either monthly or annual amounts but they must be consistent from box to box in the calculator.

Other Income

Other income is all other sources of income not contained in your employer gross amount including, but not limited to: interest and dividends, capital gains, rental income, royalty income, retirement income, trust income, disability income or workers compensation, gambling and lottery winnings, business or partnership income.

Federal Income Tax Withholding

Federal Income Tax Withholding is the amount withheld for federal taxes and is a separate line item noted on your paystub and annual tax return filed with the IRS.

State Income Tax Withholding

State Income Tax Withholding is the amount of taxes paid to the state of Illinois and is a separate line item on your paystub and annual tax return filed with the State of Illinois and the IRS.


FICA stands for The Federal Insurance Contributions Act and is the federal law that requires you to withhold two separate taxes from the wages you earn. It includes Social Security Tax and Medicare Tax at a flat percentage rate. The Social Security Tax is 6.2% of your wages, and the Medicare Tax is 1.45% of your wages. If you earn more than $200,000, you will also be taxed an additional 0.9% Medicare surtax. This number may appear as two separate items on your paycheck or simply be labeled FICA.

Mandatory Retirement Deduction

A mandatory retirement deduction is one that is required by law and does not include voluntary contributions such as an employer 401k plan. It is usually found in federal, state and teacher employment situations.

Union Dues

This is the amount paid in union dues and applies to union workers such as teachers, electricians, etc.

Health / Hospitalization Premiums

This refers to the employee portion paid in hospital, dental and vision insurance premiums to cover both the parent and the children if they are covered under the parent’s insurance plan.

Prior Support Orders Actually Paid

This amount refers to prior obligations of child support actually paid pursuant to a court order or administrative order. Prior obligations mean the family that is first in time, not the support order that is entered first.

Maintenance / Alimony Support Payments

Enter the amount you pay in alimony or spousal support payments pursuant to a court or administrative order.

Number of Children

Enter the number of children under 18 or who have not yet graduated from high school. If a child has turned 18 but is still in high school, include them in this number.

Illinois Child Support Calculator