Illinois Divorce Maintenance: Eligibility, Formula, and Duration

In an Illinois divorce, maintenance (formerly alimony) is awarded in two steps: the judge first decides whether support is appropriate using a 14-factor eligibility test, then applies a statutory formula that takes 33⅓% of the paying spouse’s net annual income and subtracts 25% of the receiving spouse’s net annual income. The duration is tied to how long you were married, from a fraction of a short marriage to an indefinite term for marriages of 20 years or more.¹ The guideline formula controls when combined gross income is under $500,000 and the paying spouse has no prior support obligation.

Whether You Qualify at All

Before any formula runs, the judge decides under Section 504(a) whether maintenance is warranted. If the answer is no, maintenance is barred outright — length of marriage and income disparity notwithstanding.¹ This gatekeeping stage is where most contested cases are actually fought.

The statute lists 14 factors. The ones that carry the most weight:

Each spouse’s income, property, and needs, including wages, investments, retirement accounts, and the marital property each received in the divorce
Each spouse’s earning capacity and realistic job prospects
Any impairment to the earning capacity of the spouse seeking support because they left the workforce, delayed education, or turned down opportunities to manage the household or raise children
The standard of living established during the marriage
Duration of the marriage
Parenting responsibilities that limit a spouse’s ability to work
All sources of income, including disability, retirement, and other public or private payments

The court can also weigh contributions one spouse made to the other’s education or career, any valid agreement between the parties, and any other factor the judge finds relevant.¹

How Much the Formula Produces

When the couple’s combined gross annual income is under $500,000 and the payer has no existing child support or maintenance obligation from a prior relationship, the guideline formula in Section 504(b-1) governs.¹

The arithmetic:

33⅓% of the paying spouse’s net annual income
Minus 25% of the receiving spouse’s net annual income
Equals the annual maintenance amount

One hard cap applies. The payment cannot lift the recipient’s total income above 40% of the couple’s combined net income. If it would, the court trims the award to bring the recipient down to that ceiling.

What Counts as Net Income

Net income is not something either side calculates from a tax return. The Illinois Department of Healthcare and Family Services publishes a standardized gross-to-net conversion table, updated annually, that both sides use.² The table assumes each person files as a single taxpayer taking the standard deduction, and it accounts for federal income tax, Illinois state income tax, Social Security at 6.2%, and Medicare at 1.45%. It does not factor in credits like the Earned Income Tax Credit or Child Tax Credit. Using the same table on both sides keeps the calculation consistent and closes off tax-planning games.

A Worked Example

Say the paying spouse has $90,000 in net annual income and the receiving spouse has $30,000.

33⅓% of $90,000 = $30,000
25% of $30,000 = $7,500
$30,000 − $7,500 = $22,500 per year

Now the cap. Combined net income is $120,000, and 40% of that is $48,000. Adding $22,500 to the recipient’s $30,000 would give her $52,500, over the ceiling. So the court reduces the annual maintenance to $18,000, which brings her total to exactly $48,000.¹

When Combined Income Exceeds $500,000

Above the $500,000 threshold, the formula becomes a reference point rather than a rule. The court has full discretion to set the amount by working through the Section 504(a) eligibility factors. Judges often run the formula anyway and use the result as a starting point, but they can go above or below it. Significant departures require an explanation on the record.¹

How Long Payments Last

Duration is calculated by multiplying the length of the marriage (from the wedding to the date the divorce case was filed) by a factor that rises with the length of the marriage. Anchor points:

Under 5 years: 0.20 (a 4-year marriage = 0.8 years of support)
5 to under 6 years: 0.24
7 to under 8 years: 0.32
10 to under 11 years: 0.44
12 to under 13 years: 0.52
15 to under 16 years: 0.64 (a 15-year marriage = 9.6 years of support)
17 to under 18 years: 0.72
19 to under 20 years: 0.80

At 20 years the calculation changes character. For marriages of 20 years or more, the court can order maintenance for a period equal to the full length of the marriage, or for an indefinite term with no set end date.¹ That line is the single most consequential number in the duration analysis.

Three Types of Award

Every maintenance order must be designated as one of three types, and the label matters as much as the number:

Fixed-term. The court sets a specific end date. Once that date passes, maintenance is permanently barred with no option to extend.
Indefinite. No termination date. Payments continue until modified or terminated under Section 510.
Reviewable. The court sets a term but schedules a future review hearing. At the review, the court can extend maintenance for another period, convert it to a fixed non-modifiable term, convert it to indefinite maintenance, or terminate it.¹

Support While the Divorce Is Pending

You do not have to wait for a final judgment to get financial help. Under Section 501, either spouse can petition for temporary maintenance while the case is pending. The court usually decides these requests on a summary basis using financial affidavits, tax returns, pay stubs, and bank statements, though a full hearing can be ordered for good cause.³ Temporary maintenance is meant to cover rent, utilities, and basic living costs during the months (or years) it takes to finalize property division and set permanent support.

When the Court Departs from the Formula

Section 504(b-1) lets the court find that applying the guidelines would be inappropriate and set a non-guideline amount or duration instead. When it does, the judge must state in writing what the guideline figure would have been and explain the reason for the departure.¹ Common triggers for deviation include extraordinary medical costs, an existing support obligation from a prior relationship (which disqualifies guideline maintenance on its own), a lopsided property division, or a spouse whose earning capacity is temporarily impaired but expected to recover. The written-explanation requirement is what makes deviations reviewable on appeal.

Taxes on Maintenance

For any divorce or separation agreement executed after December 31, 2018, maintenance payments are not deductible by the payer and not taxable to the recipient. The Tax Cuts and Jobs Act of 2017 made this change permanent; it does not sunset.⁴ A pre-2019 agreement modified after 2018 gets the same treatment only if the modification expressly says the new rules apply.

Illinois follows the federal approach with no separate state-level deduction. A $3,000 monthly payment costs the payer $3,000, and the recipient keeps the full amount. If you are negotiating a settlement, work the numbers with that reality in mind. For older agreements finalized before January 1, 2019, the pre-TCJA rules still apply, so the payer deducts and the recipient reports the income.⁴

Changing the Order Later

Either party can petition to modify maintenance by showing a substantial change in circumstances. Section 510(a-5) governs the standard, and it explicitly says that the mere foreseeability of a future event is not a defense against modification unless the original order or agreement specifically identified that event and stated it would not count.⁵

On a modification petition, the court looks at the original Section 504(a) factors plus nine modification-specific factors, including:

Whether either party’s employment status changed, and whether the change was in good faith
The receiving spouse’s efforts to become self-supporting
Changes in earning capacity on either side
How long maintenance has already been paid relative to the length of the marriage
Property either party has acquired since the divorce, including retirement benefits
Changes in either party’s income since the last order

Retirement is a frequent trigger. Illinois has no statutory age that ends maintenance automatically, but courts have accepted that retiring at a reasonable age in good faith, particularly from physically or mentally demanding work, can qualify as a substantial change.⁵ The court will look hard at whether the retirement is genuine or a tactic to shed the obligation.

When Maintenance Ends Automatically

Section 510(c) ends maintenance by operation of law when any of three events happens, with no need to file for relief:

Either party dies. The obligation ends immediately. If the payer had a life insurance policy designated to secure maintenance, the recipient or their designee can still collect that death benefit.
The recipient remarries. Termination is effective on the wedding date, and the payer is entitled to reimbursement for any maintenance paid after that date. The recipient must give the payer at least 30 days’ notice before the wedding, or within 72 hours if the decision was made on shorter notice.
The recipient cohabits on a continuing, conjugal basis. Termination is effective on the date the court finds cohabitation began, with reimbursement for anything paid after that date.⁵

The cohabitation ground is heavily litigated. Occasional overnight stays are not enough; courts look for shared finances, a joint household, and a relationship that functions like a marriage. And the statute’s “unless otherwise agreed” language matters — a settlement agreement can waive some or all of these automatic termination events, and if it does, the agreement controls.

If a Spouse Stops Paying

Enforcement tools sit behind every maintenance order. The most immediate is an income withholding order sent to the payer’s employer, which pulls maintenance directly from each paycheck the way child support garnishment does.

Where a spouse has the ability to pay and willfully refuses, the court can hold them in contempt. Contempt consequences include periodic imprisonment of up to six months, with possible work-release, fines, and an order to pay the other side’s attorney fees. Driver’s licenses can be suspended when payments run 90 or more days overdue.⁶

Each missed payment automatically becomes a judgment with the full force of any other Illinois court judgment. A lien arises by operation of law against the non-paying spouse’s real and personal property for every overdue installment, so the property cannot be sold or refinanced without first clearing the debt. Unpaid support also accrues simple interest, so a balance keeps growing even without new penalties.⁶

Prenups and Maintenance Waivers

You can agree in a prenuptial or postnuptial agreement to waive or limit maintenance. Illinois courts generally enforce these waivers if the agreement is in writing, was signed voluntarily by both parties, and rested on full financial disclosure. The Illinois Uniform Premarital Agreement Act includes a safety valve, though: if enforcing the waiver would cause significant hardship at the time of the divorce, the court can override it. The evaluation happens at the time of divorce rather than when the agreement was signed, so a waiver that looked fair years ago can become unenforceable if circumstances have shifted enough.

Even short of a full waiver, Section 504(a)(13) lists “any valid agreement of the parties” as one of the eligibility factors, so a partial agreement can still shape the amount or duration.¹

1
Illinois General Assembly. Illinois Code 750 ILCS 5/504 – Maintenance
2
HFS. Illinois Schedule of Basic Obligations and Standardized Net Income Table
3
FindLaw. Illinois Code 750 ILCS 5/501 – Temporary Relief
4
Internal Revenue Service. Publication 504 – Divorced or Separated Individuals
5
Illinois General Assembly. Illinois Code 750 ILCS 5/510 – Modification and Termination of Provisions for Maintenance, Support, Educational Expenses, and Property Disposition
6
Illinois General Assembly. Illinois Code 750 ILCS 5/505 – Child Support; Educational Expenses