Spousal Maintenance in Illinois: Alimony Rules Explained

When a marriage ends in Illinois, one of the most common and contested financial questions is whether one spouse will be required to pay support to the other, and if so, how much and for how long. Illinois calls this spousal maintenance, though many people still refer to it as alimony. The two terms mean the same thing.

Maintenance is not awarded automatically in every divorce. Before any amount or duration is set, a court must first determine whether maintenance is even appropriate given the circumstances of the marriage and each spouse’s financial situation. Understanding how Illinois courts make that decision, how the amount is calculated, and when an existing order can be changed is essential for anyone going through a divorce in Sangamon County.

What Factors Affect Spousal Maintenance in Illinois?

Spousal maintenance is not automatic in an Illinois divorce. The court first decides whether one spouse needs support and whether the other spouse has the ability to pay. The judge then reviews several factors before deciding the amount, duration, and terms of support.

Factor	Why It Matters
Income and property of each spouse	The court reviews each spouse’s income, assets, debts, and property awarded in the divorce.
Financial needs of each spouse	A spouse seeking support must show a real financial need based on expenses, obligations, and available resources.
Present and future earning capacity	The judge looks at each spouse’s ability to earn income now and in the future.
Time needed for education or training	If one spouse needs time to become self-supporting, that may affect the maintenance decision.
Standard of living during the marriage	The court may consider the lifestyle established during the marriage when reviewing support.
Length of the marriage	Longer marriages often lead to longer maintenance periods if support is awarded.
Age and health of each spouse	Medical issues, disability, or age-related limits may affect income and support needs.
Childcare responsibilities	If one spouse has primary childcare duties, that may limit work availability or earning capacity.
Tax consequences	The court may review how maintenance affects each spouse financially after taxes.
Any valid agreement between spouses	Prenuptial, postnuptial, or settlement agreements may affect maintenance rights.

What Is Spousal Maintenance in Illinois?

Spousal maintenance exists to address the financial imbalance that often results when one spouse sacrificed career advancement, education, or earning capacity to support the marriage or raise children. It is a financial bridge intended to help the lower-earning spouse maintain a reasonable standard of living while building toward self-sufficiency after the divorce.

Illinois law makes maintenance gender-neutral. Either spouse can seek it, and either spouse can be ordered to pay it regardless of who filed for divorce.

The court does not automatically grant maintenance. Under 750 ILCS 5/504, the court must first review a set of statutory factors to determine whether an award is appropriate at all. These include the income and property of each spouse (including marital property being divided in the divorce), the realistic earning capacity of both parties now and in the future, any impairment to the requesting spouse’s earning capacity caused by time devoted to domestic duties or delayed education and career development during the marriage, the length of the marriage, the standard of living established during the marriage, the age and health of both spouses, and any existing premarital or postmarital agreements.

Only after finding that maintenance is appropriate does the court move to calculating the amount and duration. The fact that one spouse earns less than the other is not by itself enough to guarantee a maintenance award.

How Illinois Courts Calculate Spousal Maintenance

For divorces where the combined gross income of both spouses is less than $500,000 per year and neither party has prior child support or maintenance obligations from a previous relationship, Illinois courts use a statutory formula under 750 ILCS 5/504(b-1)(1)(A).

The formula works as follows: take 33.3 percent of the paying spouse’s net annual income and subtract 25 percent of the receiving spouse’s net annual income. The result is the annual maintenance amount.

There is a cap. The maintenance payment, when added to the receiving spouse’s own income, cannot push that spouse’s total income above 40 percent of the couple’s combined net income. If the formula produces a number that would exceed that threshold, the maintenance amount is reduced to stay within the 40 percent cap.

Net income for this purpose means income after taxes and mandatory deductions including Social Security, Medicare, and health insurance premiums. Bonuses, commissions, rental income, investment income, and other forms of compensation are generally included in the calculation.

A Simple Example

If the paying spouse has a net monthly income of $6,500 and the receiving spouse has a net monthly income of $2,500, the formula produces: ($6,500 x 33.3%) minus ($2,500 x 25%) = $2,165 minus $625 = $1,540 per month. The combined net income is $9,000. Forty percent of that is $3,600. Adding $1,540 to the receiving spouse’s $2,500 gives $4,040, which exceeds $3,600. In that case, the maintenance would be adjusted downward so the receiving spouse’s total does not exceed $3,600 per month.

The Illinois Maintenance Formula Explained

When combined gross income exceeds $500,000 per year, or when a party has prior maintenance or child support obligations from a previous relationship, the formula does not automatically apply. In those cases, the court uses the 14 statutory factors in 750 ILCS 5/504(a) to determine an appropriate amount on a case-by-case basis. Even in formula cases, a court can deviate from the guideline amount if the specific facts of the case justify a different result.

Why Online Alimony Calculators Often Get It Wrong

Online alimony calculators can give a rough estimate, but they do not decide whether maintenance will actually be awarded in the first place. In Illinois, the court must first determine whether maintenance is appropriate, and even when the statutory formula applies, the final number can still be limited by the 40 percent cap or adjusted based on the facts of the case. That means a calculator can help you understand the range, but it cannot replace a case-specific review of income, marriage length, and the statutory factors that drive the court’s decision.

How Long Spousal Maintenance Lasts in Illinois

The duration of maintenance under Illinois law is tied directly to the length of the marriage. The longer the marriage, the longer the maintenance obligation. Under 750 ILCS 5/504(b-1)(1)(B), the duration is calculated by multiplying the length of the marriage by a statutory percentage that increases with marriage length.

• Marriage under 5 years: maintenance for 20 percent of the marriage length
• Marriage of 5 to 10 years: maintenance for 40 percent of the marriage length
• Marriage of 10 to 15 years: maintenance for 60 percent of the marriage length
• Marriage of 15 to 20 years: maintenance for 80 percent of the marriage length
• Marriage of 20 years or more: court may award maintenance for a period equal to the length of the marriage or for an indefinite term

For a 10-year marriage, that means roughly 4 years of maintenance. For a 15-year marriage, roughly 9 years. For marriages of 20 years or longer, the court has discretion to order support that mirrors the length of the marriage or continues indefinitely.

Types of Spousal Maintenance Awards

Illinois courts issue four types of maintenance designations under 750 ILCS 5/504(b-4.5). Fixed-term maintenance has a specific end date after which no further payments are owed. Indefinite maintenance has no designated termination date and continues until the court modifies or terminates it under Section 510. Reviewable maintenance is ordered for a specific term but is subject to court review at the end of that period. Reserved maintenance preserves the court’s right to award support later without ordering payments immediately.

The type of maintenance awarded matters significantly because it affects how and when the obligation can later be changed.

When Spousal Maintenance Ends Automatically

Certain events end a maintenance obligation by operation of law, meaning the paying spouse does not need to file anything with the court for the obligation to stop.

Maintenance terminates automatically when the receiving spouse remarries. Illinois law requires the receiving spouse to notify the paying spouse at least 30 days before remarrying, or within 72 hours if the remarriage was not planned in advance. Any maintenance paid after the date of remarriage must be returned to the paying spouse.

Maintenance also terminates automatically upon the death of either party. The estate of a deceased paying spouse does not continue the obligation, and the heirs of a deceased receiving spouse have no right to continue receiving payments unless a life insurance arrangement was specifically built into the divorce judgment.

When Maintenance Can Be Modified or Terminated

Outside of the automatic termination events, maintenance can only be modified or ended through a formal court proceeding under 750 ILCS 5/510. The party seeking a change must demonstrate a substantial change in circumstances since the original order was entered.

A substantial change in circumstances can include a significant increase or decrease in either spouse’s income, job loss by the paying spouse, a disabling medical condition affecting either party’s ability to work or need for support, or the receiving spouse’s failure to make reasonable efforts toward self-sufficiency when self-sufficiency was a stated goal of the maintenance award.

Does Cohabitation End Maintenance in Illinois

Illinois is one of relatively few states that allows maintenance to be terminated when the receiving spouse begins living with a new partner in a relationship that resembles a marriage. This is called conjugal cohabitation under 750 ILCS 5/510(c). Unlike remarriage, cohabitation does not terminate maintenance automatically. The paying spouse must file a petition with the court and prove that the cohabitation qualifies as a de facto marital relationship.

Courts look at the totality of the circumstances, including the length of the relationship, how much time the couple spends together, whether they vacation and spend holidays together, whether their finances are intermingled, and the overall nature of their domestic arrangements. Simply having a roommate or dating someone does not meet the standard. The relationship must resemble a marriage in a meaningful way.

2025 Law Update: Maintenance Continues During Incarceration

A significant 2025 change to Illinois law under Public Act 103-967 removed the prior practice of automatically pausing maintenance during the paying spouse’s incarceration. Effective January 1, 2025, a maintenance obligation continues to accrue as a legal debt during any period of incarceration. The paying spouse must file a formal petition for modification if they cannot pay due to imprisonment. Waiting does not stop the debt from growing.

How to Modify Spousal Maintenance in Sangamon County

Maintenance cases in Sangamon County are handled in the 7th Judicial Circuit. A petition to modify or terminate maintenance must be filed in the same court that entered the original order. The modification takes effect only for payments accruing after the other party receives notice of the petition. You cannot retroactively undo payments that already came due before the petition was filed.

The court does not apply the statutory formula when reviewing a modification request. The focus is on whether the current circumstances justify a change to the existing order, not on what the original formula would produce today.

If a modification is granted, the court can increase, decrease, extend, or terminate the maintenance obligation. It can also convert a fixed-term award to an indefinite one if circumstances warrant, or terminate maintenance entirely.

Why Spousal Maintenance Decisions Affect Long-Term Finances

Whether you are the spouse likely to pay maintenance or the spouse likely to receive it, the amount and duration of that obligation will shape your financial picture for years after the divorce is final. Errors in how net income is calculated, failure to document career sacrifices made during the marriage, or accepting an informal arrangement instead of a court order all create problems that are difficult to fix later.

A family law attorney in Sangamon County can help ensure that the financial disclosures are accurate, that the statutory factors are fully presented to the court, and that any agreement reflects your actual circumstances rather than assumptions made under pressure during an emotionally difficult time.

Bottom Line: Maintenance Depends on Eligibility, Income, Timing, and Proof

Is spousal maintenance automatic in Illinois divorce cases? No. Maintenance is not awarded in every divorce. The court must first determine whether it is appropriate based on the financial circumstances of both spouses, the length of the marriage, and other statutory factors under 750 ILCS 5/504. A significant income gap between spouses does not automatically result in a maintenance award.

How is the amount of spousal maintenance calculated in Illinois? For most divorces where combined gross income is under $500,000, Illinois uses a formula: 33.3 percent of the paying spouse’s net income minus 25 percent of the receiving spouse’s net income equals the annual maintenance amount. The result is capped so the receiving spouse’s total income does not exceed 40 percent of the couple’s combined net income.

Can either spouse seek spousal maintenance in Illinois? Yes. Illinois maintenance law is gender-neutral. Either spouse can seek maintenance and either spouse can be ordered to pay it, regardless of who filed for divorce. The decision is based on financial circumstances and the statutory factors, not on gender or the reason for the divorce.

How long does spousal maintenance last in Illinois? Duration depends on the length of the marriage. A marriage under 5 years produces maintenance for 20 percent of that length. Marriages of 5 to 10 years produce 40 percent. Marriages of 10 to 15 years produce 60 percent. Marriages of 15 to 20 years produce 80 percent. For marriages of 20 years or more, the court may award maintenance for the full length of the marriage or indefinitely.

Can a maintenance order be changed after the divorce is final? Yes. Either spouse can petition the court for a modification under 750 ILCS 5/510 by showing a substantial change in circumstances. This can include significant income changes, job loss, a serious medical condition, or the receiving spouse’s failure to pursue self-sufficiency. The modification applies only to payments accruing after the other party receives notice of the petition.

Does maintenance end if the receiving spouse moves in with a new partner? It can, but not automatically. Unlike remarriage, cohabitation does not terminate maintenance by operation of law. The paying spouse must file a petition and prove that the receiving spouse is living with a new partner in a relationship that resembles a marriage. The court looks at the full circumstances of the relationship, not just whether the two people share a residence.

Frequently Asked Questions

Is spousal maintenance automatic in Illinois divorce cases?
No. Courts first determine whether maintenance is appropriate based on financial circumstances and statutory factors. A difference in income alone does not guarantee an award.

How is spousal maintenance calculated in Illinois?
For most cases under $500,000 combined income, Illinois uses a formula. It applies 33.3 percent of the paying spouse’s net income minus 25 percent of the receiving spouse’s net income. The result is capped so the receiving spouse does not exceed 40 percent of combined net income.

How long does spousal maintenance last in Illinois?
Duration depends on the length of the marriage. Shorter marriages result in shorter maintenance periods, while longer marriages increase the duration. Marriages of 20 years or more may result in long-term or indefinite maintenance.

Can either spouse receive spousal maintenance?
Yes. Illinois law is gender-neutral. Either spouse can request or be ordered to pay maintenance based on financial circumstances.