guideline formula Illinois uses a precise two‑part formula for marriages under 20 years with combined gross income < $500,000. The court must first find that maintenance is appropriate based on need and ability, then apply:
If the formula results in a combined maintenance + child support obligation > 50% of payor's net income, the court may deviate [citation:1][citation:9].
Based on net income formula for combined income under $500k:
threshold, not cap The statutory guidelines apply only when the parties' combined gross annual income is less than $500,000 and the payor has no prior support obligations [citation:1][citation:9].
In Cook County (Chicago) and DuPage County, high‑income cases often result in awards based on marital lifestyle and needs rather than formula, but the 33.3%/25% framework remains influential [citation:3][citation:8].
precise multipliers For marriages under 20 years, duration = marriage length × factor below (750 ILCS 5/504(b‑1)(1)(B)): [citation:1][citation:7][citation:9]
Marriages 20+ years: court in its discretion shall order maintenance for a period equal to the length of the marriage or for an indefinite term [citation:1][citation:3][citation:9].
📌 Example: 14‑year marriage → factor .60 → duration = 14 × 0.60 = 8.4 years. Temporary maintenance paid during divorce may be credited against this term [citation:1].
Indefinite maintenance is possible for marriages ≥20 years, but terminates upon recipient's remarriage or cohabitation [citation:3][citation:7][citation:9].
Using the guideline formula with net incomes:
Duration example: 14‑year marriage → 8.4 years. Cook County judges typically follow guidelines closely but may deviate for health or significant assets [citation:3][citation:8].
Demo: $150k net / $50k net, 16yr Marriage, Cook County
IL formula: 33.3%×150k = $50,000 − 25%×50k = $12,500 → $37,500/yr ($3,125/mo).
40% cap: combined net $200k ×40% = $80k; payee with maint = $50k+$37.5k = $87.5k → cap reduces maint to $30k/yr ($2,500/mo).
Duration: 16yr marriage × .68 = 10.9 years.
Compare NY (cap $241k gross, formula ~$3,000‑3,500/mo, duration ~6.4yrs).
Compare FL (35% net gap, ~$3,800/mo, duration 60% = 9.6yrs).
Compare TX (20% gross cap, ~$2,500‑3,000/mo, duration max 7yrs).
IL offers longer duration than TX, similar to FL, with precise formula.
💡 IL insight: Net‑income formula and 20‑tier duration make IL one of the most predictable states, but the 40% cap often reduces awards in mid‑income cases.
✅ Formula: 33.3% net − 25% net (≤$500k combined)
✅ Cap: 40% of combined net
✅ Duration: 20‑tier multipliers (20‑80%)
✅ 20+ yrs: 100% length or indefinite
✅ Tax: not deductible (post‑2018)
🔵 Formula: 20/30% gross − 20% gross
🔵 Cap: $241k payor income cap
🔵 Duration: 15‑50% brackets
🌴 Guideline: 35% net gap
🌴 Duration: 50/60/75% of marriage
🌴 No permanent (post‑2023)
⭐ Cap: 20% gross / $5,000
⭐ Duration: 5/7/10 yrs strict
⭐ Eligibility: 10yr/DV/disability
90‑day rule To file for divorce in Illinois: at least one spouse must have been a resident of Illinois for 90 days immediately before filing [citation:4].
If moving from another state: The state where the petition is first served generally retains jurisdiction. Moving after service won't automatically erase existing support orders. Consult a Cook County or DuPage County family lawyer before relocating.
Asset protection in Illinois: Illinois is an equitable distribution state (750 ILCS 5/503). Marital property includes all assets acquired during marriage (except gifts/inheritance). Courts consider contributions, length, and may award more to spouse with lower support [citation:4].
🔎 If you're planning to move to Chicago or suburbs, speak with a local family law attorney before filing elsewhere.
Effective January 1, 2025 (Public Act 103-967), maintenance obligations continue to accrue as arrears during incarceration. Payors must petition the court for modification rather than simply stopping payments [citation:3].
For combined gross income under $500,000, amount = 33.3% of payor's net income − 25% of payee's net income, with a cap so payee receives ≤40% of combined net income. Duration = marriage length × multiplier from 20‑tier schedule (20% to 80%). Marriages ≥20 years may receive indefinite or marriage‑length awards [citation:1][citation:3][citation:9].
Duration is marriage length multiplied by a statutory factor ranging from .20 (<5yrs) to="" .80="">
No hard cap, but the guideline formula only applies when combined gross income < $500,000. Above that, courts consider all statutory factors without a formula [citation:1][citation:9].
For divorces finalized after 2018, maintenance is not deductible by the payor and not taxable to the recipient under federal tax law. Illinois conforms to this rule [citation:3][citation:8].
Yes, upon substantial change in circumstances (job loss, disability, cohabitation). Unless the order expressly states it is non‑modifiable [citation:3][citation:7][citation:8].
No. Illinois courts do not consider marital misconduct (including adultery) when determining maintenance, unless it resulted in dissipation of marital assets [citation:3].
Illinois spousal maintenance information compiled from 750 ILCS 5/504, 2026 Illinois family law updates (Public Act 103-967), Cook County Domestic Relations Division Local Rules, and DuPage County family law guidelines. Figures are illustrative. Always consult an Illinois family law attorney for your specific situation.
📌 Post‑2018 tax rule: maintenance not deductible for payer, not taxable to recipient.