Nationally, people who hire a full-scope divorce attorney pay an average of $11,300 in attorney fees, according to survey data compiled by Nolo — a useful benchmark, though it isn't Illinois-specific and reflects hourly-billed cases rather than a fixed-fee model. In practice, Illinois cases run anywhere from a few thousand dollars for a straightforward, uncontested divorce to well over $20,000 for a contested case involving disputed property or custody.

What you actually pay depends on your county, whether your case is contested, and how much attorney time it requires — all of which are covered below.

The current average Illinois divorce cost is between $11,000 and $14,000 in attorney fees plus about $1,600 in additional fees, which we discuss below. Generally, the more complicated your divorce is and the more you and your spouse disagree, the more expensive it will be.

You'll pay a fee to file your petition for dissolution of marriage — Illinois's formal term for a divorce filing — when you open your case. Filing fees vary by county. In Cook County, filing costs $388, plus a $251 appearance fee once your spouse responds — a combined $639 if you file together in an uncontested case, according to the Cook County Circuit Clerk. In Lake County, filing a dissolution case (with or without children) runs $334, with a $209 appearance fee, per the Lake County Circuit Clerk's current fee schedule (effective October 1, 2025). Fee waivers are available if your household income is at or below 125% of the federal poverty level.

If your spouse doesn't sign an appearance voluntarily, you'll need to have them formally served with your petition. In Cook County, the Sheriff's Office charges $60 to serve papers filed electronically and $95 for in-person or mailed filings, per defendant. Costs can run higher if the sheriff needs multiple attempts or has to travel further to reach your spouse.

Most Illinois divorce attorneys bill by the hour against an upfront retainer. Illinois family law attorneys charge an average of $343 an hour, according to industry billing data from Clio's Legal Trends Report. Rates tend to run higher in the Chicago area than elsewhere in the state, and Illinois law prohibits attorneys from charging a contingency fee for a divorce, according to the Illinois State Bar Association.

Illinois law allows either spouse to ask for "temporary relief" while the divorce is pending — support payments, use of the home, or a protective order — since many cases take months to resolve. Temporary spousal or child support can run from a few hundred to several thousand dollars a month, depending on both spouses' incomes.

Building your case often means gathering financial records, appraisals, or expert opinions, a process courts call "discovery." Requesting copies of financial or court records costs $34.72 in handling charges plus $1.30 a page for the first 25 pages, dropping to $0.87 a page through page 50 and $0.43 a page after that, according to the Illinois Office of Comptroller's current fee schedule. Hiring a financial expert or parenting evaluator can add hundreds of dollars an hour on top of that.

How much you and your spouse agree on determines your case type, and your case type is the single biggest lever on cost.

Private mediators in Illinois typically charge $150 to $400 an hour, often split between both spouses, and the total usually lands well below what a contested trial would cost. If your disagreement involves parenting time or decision-making in a Cook County case, Family Court Services mediation is free, though it's only available by court order — a detail most divorce guides skip entirely.

Most Illinois attorneys bill by the hour against a retainer, meaning your bill can grow the longer your case takes, including time spent on calls and emails. Marble Law instead prices each step of a case up front, so you know the cost before you commit to it, without a large retainer to replenish along the way.

The tradeoff isn't just about predictability. Hourly billing can create a subtle misalignment: the longer a case takes, the more the attorney earns, regardless of whether it actually moves your case forward. A fixed-fee structure ties the price to the work itself, not the clock.

Based on Marble's internal data from 193 completed Illinois divorce cases, the typical fixed-fee case has cost between $2,753 and $5,809, with a median of $4,349. Straightforward, uncontested cases have run as low as $1,650, while highly contested cases involving significant property or custody disputes have run as high as $40,000. Get an estimate for your case to see where your situation is likely to fall before you commit to anything.

Divorcing with minor children usually costs more. Courts spend more time deciding "allocation of parental responsibilities" — Illinois's term for what used to be called custody — and a parenting time schedule, and you may need a parenting evaluator or mental health professional to weigh in. If the court orders child support, that obligation continues until your child turns 18, or 19 if they're still in high school, according to 750 ILCS 5/505.

Illinois is one of the few states with a maintenance formula written directly into the statute rather than left entirely to a judge's discretion. Under 750 ILCS 5/504, the guideline amount is 33⅓% of the paying spouse's net income minus 25% of the receiving spouse's net income, capped so the recipient's total income doesn't exceed 40% of the couple's combined net income.

How long payments last depends on the length of the marriage — a 10-year marriage, for example, typically means about 4.4 years of maintenance under the statutory formula. Litigating whether maintenance applies, and for how long, adds real time and cost to a case.

Illinois divides marital property in "just proportions" — a fair split based on each spouse's circumstances, not an automatic 50/50 division — according to 750 ILCS 5/503. Determining what counts as marital versus separate property can require attorney time, appraisals, or forensic accounting, especially with retirement accounts, a business, or a home.

Illinois law specifically requires courts to consider a pet's well-being when dividing companion animals as marital property, a rule most states don't have.

Agreement is the cheapest path through a divorce. An uncontested case, where you and your spouse settle every issue before filing, avoids most of the expenses that come with trial prep and repeated court dates.

Mediation is the next-cheapest option if you can't agree on everything but want to avoid a full trial. If your disagreement is limited to parenting time or decision-making in Cook County, ask whether free Family Court Services mediation applies before hiring a private mediator.

Before your first attorney consultation, gather what you can: recent tax returns, pay stubs, account statements, and a list of debts in either spouse's name. Attorneys can move faster, and bill less, when they're not starting from scratch.

An attorney with Marble Law can estimate your likely costs up front based on your specific situation, negotiate temporary support so you're not covering bills alone while the case is pending, and flag which issues are worth contesting versus settling to keep your total cost down.

The total cost of your Illinois divorce depends far more on what you and your spouse can agree on than on which county you file in. Getting a clear-eyed answer early, from filing fees to the likelihood of a contested trial, is the best way to budget for what's ahead.

Disclaimer: Laws and procedures vary by state and jurisdiction. This article provides general information and should not be considered legal advice for your specific situation. For personalized guidance, consult with an attorney.