How a Pension’s Marital Share Is Calculated: The Coverture Fraction in Illinois
Illinois presumes pension benefits acquired during the marriage are marital property and divides marital property in just proportions without regard to marital misconduct. The time-rule fraction only illustrates the marital part.
What does Illinois say about dividing a pension?
Marital property is all property, including debts and other obligations, acquired by either spouse after the marriage, except non-marital property (750 ILCS 5/503(a)). Pension benefits acquired by a spouse during the marriage are presumed to be marital property regardless of which spouse participates in the plan, and a spouse can overcome the presumption only by showing the benefits were acquired by a non-marital method; the right to a division of pension benefits in just proportions is enforceable under section 1-119 of the Illinois Pension Code (Public Act 100-871).
How does the court divide marital property in Illinois?
It divides the marital property without regard to marital misconduct in just proportions considering all relevant factors, including each party’s contribution to the acquisition, preservation or increase or decrease in value of the marital or non-marital property, and any dissipation of the marital property (503(d)). The statute does not name a percentage or a pension formula.
What is non-marital property in Illinois?
Property acquired by gift, legacy or descent or in exchange for such property; property acquired in exchange for property acquired before the marriage; property acquired after a judgment of legal separation; and property excluded by a valid premarital or postnuptial agreement, among others listed in 503(a). A pension earned before the marriage is therefore non-marital, and the calculator shows it as the part outside the marital fraction.
What is a coverture fraction in Illinois?
It is a common way to find the marital part of a defined-benefit pension: months of service earned during the marriage divided by total months of service, applied to the benefit. Illinois’s statute does not prescribe it; we use it for illustration only, and the share is your own assumption in the Illinois pension division calculator.
How does the calculation work in a worked example in Illinois?
As an example, suppose a pension of $3,000 a month with 300 months of service, of which 180 months were during the marriage. The marital fraction is 60%, so the marital part is $1,800 a month. At a 50% share, the other spouse’s illustrative share is $900 a month and the plan holder keeps $2,100.
| Example figure | Value |
|---|---|
| Service during the marriage | 180 months |
| Total service | 300 months |
| Marital fraction | 60% |
| Marital part of the benefit | $1,800 |
| Illustrative share at 50% | $900 |
| Plan holder keeps | $2,100 |
This is a labeled example, not a prediction; a court may pick a different share or method.
How is a pension actually paid to the other spouse in Illinois?
For plans under the Illinois Pension Code, the division is carried out by a Qualified Illinois Domestic Relations Order, and recognizing pension benefits as marital property and dividing them that way is not a diminishment, alienation or impairment of those benefits (Public Act 100-871). Private plans use a qualified domestic relations order (26 U.S.C. 414(p); 29 U.S.C. 1056(d)(3)). Ask the plan before the judgment is drafted.
Does fault matter for the pension in Illinois?
No. The court divides marital property without regard to marital misconduct (503(d)), though dissipation of marital property is a factor. Fault is also not a ground for divorce. See the Illinois alimony calculator and the Illinois property division calculator.
Frequently asked questions
How is a pension divided in an Illinois divorce?
As marital property to the extent acquired during the marriage, in just proportions without regard to marital misconduct.
What is a coverture fraction in Illinois?
Months of service during the marriage over total months of service. Illinois does not prescribe it; it is an illustration.
Who enforces an Illinois pension division?
For plans under the Pension Code, the right is enforceable under section 1-119 through a Qualified Illinois Domestic Relations Order.
Is premarital retirement divided in Illinois?
Property acquired before the marriage is non-marital, though contributions to it can be considered.
How does an Illinois court order a pension to be paid to a spouse?
By a domestic relations order, such as a Qualified Illinois Domestic Relations Order or a QDRO, that the plan accepts.
Official sources
- 750 ILCS 5/503: disposition of property and debts
- Public Act 100-871: pension benefits as marital property
- 750 ILCS 5/504: maintenance
- 10 U.S.C. 1408: military retired pay in divorce
- 26 U.S.C. 414(p): qualified domestic relations orders
- 29 U.S.C. 1056(d)(3): ERISA domestic relations orders
A local family law attorney can review your situation — many offer a free consultation.
This is general information, not legal advice. It is based on the cited Illinois statutes, rules and court opinions, and every case turns on its own facts. Confirm how the law applies to your situation with a licensed Illinois attorney.