Illinois Alimony & Spousal
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Illinois uses a statutory formula to calculate maintenance, providing a more predictable framework for divorcing spouses than pure judicial discretion. Under 750 ILCS 5/504, the court applies a mathematical formula based on each spouse's gross income to determine both the amount and duration of alimony payments.

While the formula provides a presumptive guideline, Illinois courts retain the ability to deviate from it when circumstances warrant.

The formula-based approach in Illinois was designed to reduce divorce litigation costs and increase consistency across family law cases. The state's formula considers formula: (33.3% of payor's net income) minus (25% of payee's net income), capped at 40% of combined net income; duration based on marriage length multiplier.

However, the formula is just a starting point — judges may adjust the final maintenance award based on the specific facts of each case, including the standard of living during the marriage, the age and health of both parties, and the distribution of marital property.

Use our Illinois alimony calculator above to estimate your maintenance obligation or entitlement based on the formula. Whether you are the paying spouse or the receiving spouse, the formula output gives you a realistic range to negotiate from before engaging with an attorney.

Family law attorneys in Chicago and across Illinois can explain how local courts apply the formula in practice and whether your facts support a deviation.

Illinois recognizes several types of maintenance: temporary, fixed-term, reviewable, indefinite. Each serves a different purpose and applies under different divorce circumstances.

The type of alimony awarded depends on the length of the marriage, the financial circumstances of both spouses, and the specific needs demonstrated by the requesting party.

Temporary alimony (also called pendente lite maintenance) is awarded during the divorce proceedings to maintain the financial status quo while the case is pending. This type of support ensures that the lower-earning spouse can cover living expenses — including housing, utilities, and basic needs — until Illinois courts issue a final maintenance order.

Temporary support automatically terminates when the final divorce decree is entered.

Permanent (or indefinite) maintenance may be awarded in long-term marriages, typically those lasting 20 years or more, or when the receiving spouse is unable to become self-supporting due to age, disability, or chronic illness. Despite the name, permanent alimony can still be modified or terminated under certain circumstances such as remarriage, cohabitation, or a material change in financial circumstances.

Illinois courts have broad discretion in determining whether to award permanent support.

Illinois uses a statutory formula to determine presumptive maintenance amounts based on each spouse's gross income. The formula works as follows: formula: (33.3% of payor's net income) minus (25% of payee's net income), capped at 40% of combined net income; duration based on marriage length multiplier.

This mathematical approach provides a starting point that both parties and their family law attorneys can use to estimate likely alimony obligations before going to court. For example, if the higher earner brings home $8,000/month and the lower earner makes $3,000/month, the formula produces a specific presumptive figure that the court can then adjust based on the circumstances of the case.

The formula calculates a presumptive amount, but Illinois courts are not strictly bound by it. Judges may deviate from the formula result if the presumptive amount would be unjust or inappropriate given the specific circumstances of the divorce.

Common reasons for deviation include significant disparity in assets, one spouse's contribution as a homemaker, family violence, or the tax consequences of the maintenance award.

Duration of alimony is also guided by statutory formulas in Illinois, typically based on a percentage of the length of the marriage. For shorter marriages, maintenance duration in many jurisdictions runs **15–30%** of the marriage length as a general benchmark — though Illinois courts retain discretion to deviate based on the specific circumstances of each case.

For marriages exceeding 20 years, courts may award indefinite alimony. Use our Illinois alimony calculator to estimate both the amount and duration based on your specific monthly gross income figures and marriage length.

Illinois calculates maintenance amounts using a statutory formula under 750 ILCS 5/504. The guideline amount equals 33.3% of the payor's monthly net income minus 25% of the payee's monthly net income, with a cap so that the combined household share does not exceed 40% of combined net income.

This formula applies when the combined gross income of both spouses does not exceed $500,000 per year. For higher-income couples, courts exercise discretion using the 12 statutory factors in 750 ILCS 5/504(a), including earning capacity, the standard of living, and each party's tax obligations.

Duration is set using a multiplier table: marriage length is multiplied by a statutory factor to determine the guideline maintenance period. A 5-year marriage uses a 0.20 multiplier (1 year of maintenance); a 10-year marriage uses 0.44 (4.4 years); a 15-year marriage uses 0.64 (9.6 years); a 20-year marriage uses 0.80 (16 years).

For marriages of 20 or more years, courts may award maintenance for a period equal to the length of the marriage or indefinitely. These guidelines apply when the court does not find sufficient reason to deviate — Cook County (Chicago) courts may adjust based on the case-specific § 504(a) factors.

The length of the marriage is the single most important factor in determining how long alimony lasts in Illinois. Short-term marriages (generally under 10 years) rarely result in long-term alimony awards.

When maintenance is granted for a short marriage, it is typically rehabilitative and limited to 2–5 years — enough time for the receiving spouse to become self-supporting through education or training.

For moderate-length marriages (10–20 years), maintenance duration in Illinois is often set as a percentage of the marriage length. As a general benchmark used by many courts, that figure falls in the range of **30–50%** of the marriage — though Illinois judges have discretion to award more or less based on the specific facts.

A 15-year marriage, for example, might result in a alimony award lasting 5–7 years. The specific duration depends on factors like the age of the receiving spouse, their earning capacity, and whether they sacrificed career opportunities during the marriage.

Long-term marriages (20+ years) may qualify for indefinite or permanent maintenance in Illinois, particularly when the receiving spouse is older, has limited earning capacity, or made significant career sacrifices to support the family. Even permanent alimony is subject to review and modification if circumstances change substantially — for example, if the paying spouse retires or the receiving spouse begins cohabiting with a new partner.

Under the Tax Cuts and Jobs Act (TCJA) of 2017, alimony payments pursuant to divorce agreements executed after December 31, 2018 are no longer tax-deductible for the paying spouse or taxable income for the receiving spouse. This was a major change from prior law, where the payor could deduct maintenance payments and the recipient reported them as gross income.

If your divorce was finalized before 2019 and you have not modified the agreement, the old tax rules may still apply to your payments. See IRS Publication 504 (Divorced or Separated Individuals) for the federal tax treatment that applies regardless of state.

Spousal maintenance orders in Illinois can be modified if either spouse demonstrates a material change in circumstances. Common grounds for modification include significant changes in income (job loss, disability, retirement, or substantial raise), changes in the receiving spouse's financial needs, or the receiving spouse becoming self-supporting sooner than expected.

The party seeking modification bears the burden of proving the changed circumstances to Illinois courts.

Spousal maintenance in Illinois typically terminates automatically upon the remarriage of the receiving spouse or the death of either party. Illinois also allows termination or reduction of alimony if the receiving spouse enters into a supportive cohabitation arrangement — essentially living with a new partner in a marriage-like relationship.

For general information on divorce and support rights, USA.gov's divorce guide provides a plain-language overview of the legal steps involved. To find a qualified family law attorney in Illinois, see the ABA Family Law Section's attorney locator.

Consult a family law attorney if any of these circumstances apply to your situation.

In Illinois, child support and alimony are calculated separately but interact with each other. Most Illinois courts calculate child support first using the state's child support guidelines — use the Illinois Child Support Estimator to see how that figure is determined — then determine maintenance based on the remaining gross income available to each spouse.

This sequencing matters because child support obligations reduce the paying spouse's available income for alimony purposes. Some states impose a combined cap, limiting total support payments (child support plus maintenance) to a percentage of the payor's gross income, often **40–50%**.

Unlike child support, which follows formulaic guidelines tied to income changes, alimony modification generally requires a more substantial showing of changed circumstances. Child support generally takes priority in Illinois — if the paying spouse's income drops, courts typically preserve child support obligations before adjusting maintenance obligations.

Child support also ends when the child reaches the age of majority, which may trigger a review of alimony if the paying spouse's financial picture changes significantly during the divorce process.

Alimony is one component of the overall divorce financial picture. The Illinois Divorce Cost Estimator projects total attorney fees and filing costs for your case.

For divorces with children, the Illinois Child Support Estimator calculates guideline support amounts using Illinois's income model. And for marital property allocation, the Illinois Property Division Calculator covers Illinois's equitable distribution or community property rules.