Divorce in Illinois: Costs, Laws, and Calculators (2026)

Everything you need to understand the financial reality of divorce in Illinois. State-specific costs, formulas, and free calculators.

Our estimate, uncontested
$2,000 - $5,500
Our estimate, contested
$13,000 - $45,000
Estimated timeline
4 - 14 months
DCE State Score
64 / 100

Illinois divorces typically cost 28% less than the national average of $12,900.

Illinois uses a statutory maintenance formula, with duration set by a multiplier that rises with every year of the marriage.

Our record has Illinois as a no-fault only state, one of twenty states we record as allowing no other ground. The only ground for dissolution is "irreconcilable differences." Maintenance is set by statute where the couple qualifies: 750 ILCS 5/504 calculates the amount from the difference between the two net incomes and the term from the length of the marriage times a multiplier fixed for each year of it, which makes support more predictable here than in a purely discretionary state. The statute also says maintenance is decided without regard to marital misconduct, so conduct does not enter the support question at all. Illinois courts apply the "best interests of the child" standard without a statutory presumption of equal time, giving judges significant discretion in custody matters. Cook County (Chicago) has heavily congested courts, particularly for contested cases.

What this section says about Illinois's parenting-time presumption is a characterisation this site carries rather than a finding. That is our own record rather than Illinois's own law.

Key Fact

Illinois sets maintenance duration by arithmetic rather than by bands: the length of the marriage times a multiplier that rises from .20 below five years to .80 at nineteen, with an open-ended term at twenty or more. Our duration figures are that calculation. Our dollar figures are not, because the statute works the amount out from net income and our calculator collects gross.

Recent Development

Illinois SB 3524 was approved by the Governor on July 31, 2026 and is Public Act 104-0733. It takes effect January 1, 2027, so an order entered today runs on the current rule and none of it is in our Illinois calculator yet. Shared physical care will begin at 110 overnights a year rather than 146, and a court, or the parents by agreement, may count certain periods of substantial daytime care as overnight equivalents where the child is in a parent's physical care and under direct supervision without sleeping there. A new table in 750 ILCS 5/505(a)(3.8)(3) will then raise the shared care obligation for a parent below 146 overnights, by 10 percent just above the 110 mark down to 2 percent for a parent on 140 to 145 overnights, and the adjusted figure may not come out above what the ordinary guideline would have produced. 146 stays the pivot: at 146 and above the calculation runs without that adjustment, so this lowers the entry point rather than replacing the number. The act also sets a minimum order of $40 per month per child for an obligor at or below 100 percent of the federal poverty guideline for one person, with the total across all of that obligor's children capped at $120 a month. Separately, 750 ILCS 5/510, the modification statute, gains a presumption that a parent incarcerated for more than 180 consecutive days cannot pay, worked through a filed notice of incarceration, a 45-day window to object, and reinstatement 90 days after release.

Illinois Divorce Quick Facts

State law, attorney rates, and procedural rules for Illinois.

Property division system, in our record
Equitable Distribution (judicial discretion)
How alimony is decided, in our record
Statutory formula
Child support formula
Income Shares Model
Mandatory waiting period
None
Residency requirement
90 days
Mediation required, in our record
No
Equal parenting presumption, in our record
No
Fault divorce available, in our record
No
Collaborative divorce available
Yes, and our record says the same for all fifty states
Filing fee range
$289 - $388
Attorney hourly rates, our estimate
$250 - $500/hour
Filing fee last checked
Not independently verified

Where these Illinois figures come from, since it is fair to ask. The court filing fee is the one we have gone back to, and even there we are recording what a fee schedule says rather than citing a document we have opened. Everything else on this page that is a cost or a length of time - attorney rates, the mediator's per-session rate, QDRO preparation, the average totals, the typical number of months - came into our data when the site was first built, and nobody has checked any of it against a published source since. Our own value distributions give the game away: attorney rates across all fifty states take seven distinct values at the low end, every one of them a multiple of 25, which is what a set of estimates looks like rather than fifty separate readings. We think they are in the right neighbourhood. We are not going to call them Illinois averages. For a real number, an Illinois family law attorney will quote you their own rate, and the clerk of court in your county will tell you the filing fee to the dollar.

The waiting period and the residency requirement in that table are in the same position, and they matter more, because a wrong number there is a filing in the wrong place rather than a bad estimate. Both came into our data at the original build and nobody here has read Illinois's dissolution statute. Confirm both with the clerk of court in the county where you will file, and ask specifically whether the wait runs from the day you file or from a separation date, because states do it both ways and our records hold one number for both cases.

DCE State Score Breakdown

Our proprietary index ranks every state on cost, complexity, and timeline. Higher is more favorable.

Overall DCE State Score

64/ 100

A score of 64 means Illinois is roughly average in terms of divorce cost and complexity.

Cost Score

24/ 40

Based on filing fees, attorney rates, and total typical costs in Illinois.

Complexity Score

30/ 30

Reflects judicial discretion, mandatory mediation, and procedural hurdles.

Timeline Score

10/ 30

Driven by waiting periods and average case duration from filing to decree.

Divorce Calculators for Illinois

All 15 calculators preconfigured for Illinois.

Illinois Divorce Laws Overview

Property Division

Our record has Illinois as an equitable distribution state. That is our own record rather than Illinois's own property division law. Equitable does not mean equal, it means fair, based on the circumstances. Judges consider factors including each spouse's income and earning capacity, contributions to the marriage, length of the marriage, and the economic circumstances of each spouse. Outcomes can vary significantly from case to case.

Spousal Support (Alimony)

Illinois writes its spousal support calculation into the statute, and it is the one state on this site whose statute we have read. 750 ILCS 5/504, the maintenance section of the Illinois Marriage and Dissolution of Marriage Act sets the amount from the difference between the two net incomes and the term from the length of the marriage multiplied by a factor fixed for each year of it. Our alimony calculator runs that duration calculation. It does not run the amount calculation, because the statute works that from net income and the calculator collects gross, so the dollar figure there is a national approximation of ours and the page says so beside it.

Child Support

Illinois uses the Income Shares Model for child support, and we have read the guideline that says so. In that model both parents' incomes are combined, a total support obligation is set from that combined figure and the number of children, and each parent's share is proportional to their share of the combined income. The paying parent pays their share to the receiving parent. The figure Illinois's own guideline works from is combined net income, under 750 ILCS 5/505(a)(1.5), applied to the Income Shares Schedule Based on Net Income.

Custody and Parenting Time

Illinois courts determine custody on the best interests of the child. Our record carries no presumption of equal parenting time for the state and puts judicial discretion here in the middle of its three-point scale. That is our own record rather than Illinois's own custody law. Courts generally favor arrangements that allow both parents meaningful involvement in the child's life.

This estimate is for planning purposes only and does not constitute legal or financial advice. Consult a licensed family law attorney in your state for guidance specific to your situation.

Recent Law Changes in Illinois

All state updates

Notable updates to Illinois family law that affect divorce outcomes and costs.

Illinois Lowers the Shared Parenting Threshold to 110 Overnights from 2027

Major

Takes effect January 2027Signed into law and not in force yet, as we last checked on August 6, 2026. Nothing in it applies to a case decided today, and none of it is in our estimate until it takes effect.

Nothing about an Illinois order entered today changes. If you are negotiating a parenting schedule that will still be running in 2027, the 110-overnight figure is worth knowing, because a schedule short of 146 nights today could reach the shared care route from January 1 and change what is paid. We cannot tell you which way it moves, and that is not a hedge: the act directs the Department of Healthcare and Family Services to publish the worksheets the calculation runs on, and those do not exist yet. What the text does say is that the adjustment between 110 and 145 nights raises the shared care obligation rather than discounting it, and that the adjusted figure may not exceed the ordinary guideline amount. Our Illinois estimate applies the current 146-overnight rule under 750 ILCS 5/505(a)(3.8), and we will build the new mechanism once those worksheets are published rather than substituting arithmetic of our own.

Illinois Continues to Refine Maintenance Formula Application

Moderate

Our record dates this to January 2023No statute or court rule took effect on this date. What is described here is how courts have been deciding, or a requirement that has not changed.

Illinois couples with combined income near or above the statutory threshold should expect outcomes to depend more on judicial discretion. Documenting marital standard of living and each spouse's earning trajectory is increasingly important for predictable awards.

No document behind this change has been opened here. The link goes to Illinois's own site rather than to the instrument, so read the change itself as our record.

Frequently Asked Questions

How much does a divorce cost in Illinois?
Our working estimate is $2,000 - $5,500 for an uncontested Illinois divorce and $13,000 - $45,000 for a contested one, with the spread depending on attorney involvement, custody disputes, and the complexity of the marital estate. Court filing fees alone are $289 - $388. Both totals are ours rather than measured averages: they came into our data when this site was built and no survey stands behind them.
How long does a divorce take in Illinois?
Our records show no mandatory wait in Illinois, an uncontested case at roughly 4 months, and a contested one at about 14. Treat all three as ours rather than as findings: we have not read Illinois's dissolution statute or its court caseload statistics. The clerk of court in the county where you will file can confirm the wait, and whether it runs from filing or from a separation date, which differs by state.
How is property divided in Illinois?
Our record has Illinois as an equitable distribution state. That is our own record rather than Illinois's own property division law. Equitable does not mean equal, it means fair, based on the circumstances. Judges consider factors including each spouse's income and earning capacity, contributions to the marriage, length of the marriage, and the economic circumstances of each spouse. Outcomes can vary significantly from case to case.
How is child support calculated in Illinois?
Illinois uses the Income Shares Model for child support, and we have read the guideline that says so. In that model both parents' incomes are combined, a total support obligation is set from that combined figure and the number of children, and each parent's share is proportional to their share of the combined income. The paying parent pays their share to the receiving parent. The figure Illinois's own guideline works from is combined net income, under 750 ILCS 5/505(a)(1.5), applied to the Income Shares Schedule Based on Net Income.
How is alimony determined in Illinois?
Illinois writes its spousal support calculation into the statute, and it is the one state on this site whose statute we have read. 750 ILCS 5/504, the maintenance section of the Illinois Marriage and Dissolution of Marriage Act sets the amount from the difference between the two net incomes and the term from the length of the marriage multiplied by a factor fixed for each year of it. Our alimony calculator runs that duration calculation. It does not run the amount calculation, because the statute works that from net income and the calculator collects gross, so the dollar figure there is a national approximation of ours and the page says so beside it.

Divorce Costs in Nearby States

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