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

By our own estimates, Illinois divorces cost about 28% less than our national working figure 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.

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 applies from January 1, 2027, and a calculation for a date before that runs on the earlier rule. From January 1, 2027, shared physical care begins 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 that parent's direct care without staying overnight. A table in 750 ILCS 5/505(a)(3.8)(3) then raises 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 the act lowers the entry point rather than replacing the number. The act also moves the line for the minimum order of $40 per month per child from 75 to 100 percent of the federal poverty guideline for one person, measured on the obligor's actual or imputed gross income, 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, in our record
None
Residency requirement, in our record
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 uncontested and contested totals, the number of months a case takes - 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

On our own 0 to 100 scale, a score of 64 puts Illinois in the band we call moderate, which runs 50 to 69. The cut points are ours, set when we built the score, and they compare Illinois with no average.

Cost Score

24/ 40

The midpoint of the uncontested cost range we hold for Illinois, against a national baseline of ours. A higher cost lowers the score.

Complexity Score

30/ 30

Lowered by a longer waiting period, a longer residency requirement, a mediation requirement, a discretionary approach to alimony and more judicial discretion over custody, and raised by an equal-parenting presumption and collaborative divorce being available, each as we hold it for Illinois.

Timeline Score

10/ 30

Based on our own contested duration estimate for Illinois and the uncontested duration our pages show for it, which is never below its waiting period, each against a national baseline of ours. A longer case lowers the score.

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 calculation our alimony calculator runs. 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

In force from January 2027Signed into law, as we last checked on August 6, 2026. A calculation for a date before January 1, 2027 runs on the earlier rule, and our calculator applies this one from that day by itself.

Our Illinois calculator applies the earlier rule to a calculation run before January 1, 2027 and this act's rule from that day, by itself. Under the act, a schedule giving one parent between 110 and 145 overnights a year reaches the shared care route where the earlier rule did not, and for that range the calculator shows no figure. That is not a hedge. The text gives the 1.5 multiplier, the split by income share, the weighting by time, the percentage for each band of overnights and a cap, and it does not say which figure the percentage is applied to or in what order it meets the offset between the two parents. It directs the Department of Healthcare and Family Services to publish the worksheets the calculation runs on, and the department had published none under the new text when its pages were checked on October 11, 2026. What the text does fix is that the adjustment raises the shared care obligation of the parent below 146 overnights rather than discounting it, and that the adjusted figure may not exceed the ordinary guideline amount. Because the two parents' obligations are then offset, that does not tell you which way the payment itself moves. Below 110 overnights for either parent, and at 146 or more for both, the calculator gives a figure under either rule.

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 calculation our alimony calculator runs. 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

See all 50 states