Family Law Playbook — Illinois Edition · Step 8 of 12
Maintenance in Illinois
The statutory formula, duration multipliers, and how courts decide maintenance under 750 ILCS 5/504
Illinois uses a maintenance formula
Illinois uses “maintenance” as the statutory term for what many other states call alimony or spousal support. Unlike states where maintenance is entirely discretionary, Illinois has a statutory formula under 750 ILCS 5/504 that applies when the combined gross income of both parties is $500,000 or less per year.
The formula gives both parties predictability about what maintenance will be and for how long. Courts must apply the formula unless there are specific reasons to deviate, and any deviation must be explained in a written finding.
The formula: 33.33% minus 25%
The Illinois maintenance formula calculates the annual maintenance amount as follows:
Maintenance = (33.33% × payor's net annual income) − (25% × payee's net annual income)
“Net income” for maintenance purposes uses the same calculation as child support: gross income minus allowable taxes and deductions.
Example: Payor earns $120,000 net per year. Payee earns $40,000 net per year.
- 33.33% of $120,000 = $40,000
- 25% of $40,000 = $10,000
- Maintenance = $40,000 − $10,000 = $30,000 per year ($2,500/month)
The 40% combined income cap
Duration: marriage length × multiplier
The duration of maintenance is calculated by multiplying the length of the marriage (in years) by a statutory multiplier. The longer the marriage, the larger the multiplier, and the longer maintenance runs.
| Marriage length | Multiplier | Example (10-year marriage) |
|---|---|---|
| Under 5 years | × 0.20 | — |
| 5–6 years | × 0.24 | — |
| 6–7 years | × 0.28 | — |
| 7–8 years | × 0.32 | — |
| 8–9 years | × 0.36 | — |
| 9–10 years | × 0.40 | — |
| 10–11 years | × 0.44 | 10 × 0.44 = 4.4 years |
| 11–12 years | × 0.48 | — |
| 12–13 years | × 0.52 | — |
| 13–14 years | × 0.56 | — |
| 14–15 years | × 0.60 | — |
| 15–16 years | × 0.64 | — |
| 16–17 years | × 0.68 | — |
| 17–18 years | × 0.72 | — |
| 18–19 years | × 0.76 | — |
| 19–20 years | × 0.80 | — |
| 20+ years | Court discretion | Fixed period or permanent |
20-year marriages — courts can award permanent maintenance
What maintenance terminates on
Maintenance automatically terminates upon:
- Death of either party
- Remarriage of the maintenance recipient
- Cohabitation of the recipient on a resident, continuing conjugal basis (not merely dating — the standard requires a relationship akin to marriage)
Maintenance can also be modified or terminated on a showing of substantial change in circumstances of either party under 750 ILCS 5/510, such as a significant change in income for either the payor or the recipient.
When the formula does not apply
The statutory formula applies only when the combined gross annual income of both parties is $500,000 or less. When combined gross income exceeds $500,000, the court uses the discretionary factors under 750 ILCS 5/504, which include:
- The income and property of each party
- The needs of each party
- The present and future earning capacity of each party
- Impairment of earning capacity due to domestic responsibilities
- Duration of the marriage
- The standard of living established during the marriage
- Each party's contribution to the other's career or education
- Tax consequences of the property division
- Valid agreements of the parties (prenuptial agreements)
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