Estimate spousal support payments by state using the AAML formula and state-specific guidelines. See monthly amount and estimated duration — free, no signup.
Unlike child support, which uses mandatory state formulas in all 50 states, alimony calculation is far less standardized. Most states give judges significant discretion to weigh multiple statutory factors. A minority of states — including Illinois — have enacted specific formulas. Others use the AAML formula as a benchmark without making it mandatory.
The AAML benchmark formula calculates alimony as 30% of the payor's gross income minus 20% of the recipient's gross income, with the recipient's total income (wages plus alimony) capped at 40% of combined gross income. This formula is used by family law professionals as a starting point for negotiation in many states even where it is not legally required.
Illinois calculates alimony (called maintenance) as 33.3% of the payer's monthly net income minus 25% of the recipient's monthly net income, capped at 40% of combined net income. This formula is codified in state statute and applies in most Illinois cases.
California temporary spousal support follows the Santa Clara guideline formula: 40% of the higher earner's net monthly income minus 50% of the lower earner's net monthly income. Permanent support has no formula — it requires judicial weighing of 14 statutory factors.
The majority of states have no mandatory formula. Judges weigh factors including: income and earning capacity of both spouses, marriage length, standard of living during marriage, age and health, contributions (including homemaker contributions), and fault in some states.
| Factor | Effect on Amount | Effect on Duration |
|---|---|---|
| Income gap between spouses | Larger gap = higher support | Neutral |
| Length of marriage | Moderate effect | Largest single factor for duration |
| Recipient's earning capacity | Higher capacity = lower support | Higher capacity = shorter duration |
| Age and health | Poor health = higher support | Older/disabled = longer or permanent |
| Standard of living during marriage | Higher standard = higher support | Moderate effect |
| Career sacrifice (homemaker years) | Increases award | Increases duration |
| Fault (in fault states) | Can increase or decrease | Can affect duration |
| Child custody arrangement | Custodial parent may receive more | May extend if children limit earning |
Alimony duration is heavily influenced by marriage length. Most states use a rough proportion of the marriage length as a starting point, though judicial discretion applies in all states without statutory formulas.
| Marriage Length | Typical Alimony Duration | Type |
|---|---|---|
| Under 5 years | 1–3 years | Rehabilitative (short-term) |
| 5–9 years | 2–5 years | Rehabilitative |
| 10–14 years | 4–8 years | Rehabilitative to transitional |
| 15–19 years | 7–12 years | Long-term / potentially permanent |
| 20+ years | Indefinite / permanent | Permanent in many states |
Termination events: Alimony automatically ends in most states when the recipient remarries. Cohabitation with a romantic partner terminates support in many (but not all) states. Death of either party ends the obligation. Significant income changes — either earning more or less — typically trigger modification proceedings.
The tax treatment of alimony changed significantly with the 2017 Tax Cuts and Jobs Act and applies to all divorce agreements finalized after December 31, 2018.
Alimony is not tax-deductible for the payer and not taxable income for the recipient. This is the rule for all divorce agreements finalized after December 31, 2018. California adopted the same rule for state taxes effective January 1, 2026.
Agreements finalized before January 1, 2019, retain the old tax treatment: deductible for the payer and taxable income for the recipient. This treatment continues unless the agreement is modified to explicitly adopt the new rules.
The old tax treatment effectively made alimony partially funded by the IRS — the payer's deduction reduced the net cost. Under current rules, there is no tax benefit. This affects negotiation: a dollar of alimony costs the payer more and benefits the recipient less in after-tax terms than under old rules.
AAML formula, state-specific formulas, judicial discretion factors, and what courts actually look at when setting spousal support.
Read guide →State-by-state breakdown of alimony laws, which states use formulas, which use discretion, and estimate ranges at common income levels.
Read guide →Duration rules by marriage length, what terminates alimony, how cohabitation affects support, and how to modify an existing order.
Read guide →