Alimony (also called spousal support or maintenance) is a court-ordered financial payment from the higher-earning spouse to the lower-earning spouse following a divorce or legal separation. Its purpose is to recognize the economic partnership of marriage and help the lower-earning spouse maintain a reasonable standard of living while transitioning to financial independence. Unlike child support, which follows state-mandated formulas everywhere, alimony calculation varies enormously between jurisdictions — and that variance is what this calculator helps you see across six different formulas at once.
Formulas vs Judicial Discretion
Alimony calculation follows two broad approaches depending on the state. Some states — including Illinois, Massachusetts, New York, Colorado, Kansas (Johnson County), Pennsylvania for pendente lite, and Texas with statutory caps — have enacted specific formulas or binding guidelines that produce a clear starting number. Most states, however, leave alimony entirely to judicial discretion, with courts weighing 10–17 statutory factors without a prescribed calculation.
Within the formula-based approaches, three models dominate. The AAML formula (30% of payer's income minus 20% of payee's income, monthly) is the most widely used informal starting point among family law attorneys nationally. The Income Share approach (a percentage of the income difference) is used by several state guidelines and by online calculators for its transparency. The Ginsburg equalization formula, which splits the income difference in half, produces higher estimates for large income gaps and is used in a handful of jurisdictions and by some private mediators. This calculator runs all six side-by-side so you can see the range rather than anchor to a single number.
Duration and How Marriage Length Shapes Outcomes
Duration of alimony generally correlates with marriage length, and most states encode this relationship directly. Short marriages (under 5 years) typically result in alimony lasting half the marriage length or less — often bridge-the-gap support meant to cover specific near-term transitions rather than long-term income replacement. Moderate-length marriages (5 to 15 years) most often produce rehabilitative alimony for roughly 40–70% of the marriage duration, giving the recipient time to retrain, re-enter the workforce, or stabilize new income. Long marriages (15 years and up) may qualify for long-term or permanent alimony, particularly when one spouse prioritized the household over career development and cannot reasonably reach self-support by retirement age. Texas caps spousal maintenance duration at 5, 7, or 10 years depending on marriage length tier; Massachusetts uses percentages of marriage length (50%, 60%, 70%, 80% for the length bands); Illinois applies a table of multipliers ranging from 0.20 to 1.0. Most discretion states follow similar logic through case-law patterns rather than statute.
Tax Treatment and Modification Rights
A major tax change took effect for divorces finalized after December 31, 2018, under the Tax Cuts and Jobs Act. Under the old rules, the paying spouse could deduct alimony payments from taxable income, and the recipient reported alimony as income, creating a meaningful net tax efficiency that often helped settlements close. Under the current post-TCJA rules, alimony is neither deductible for the payer nor taxable for the recipient, which effectively raises the real cost to the payer and has measurably pushed more cases toward lump-sum settlements instead of ongoing monthly payments. Alimony can also be modified after the decree if there is a substantial change in circumstances — a major income change, involuntary job loss, disability, retirement, or the recipient's remarriage or supportive cohabitation. Building clear modification triggers into your divorce agreement is important because some forms of alimony (bridge-the-gap and certain durational orders) are non-modifiable by statute. This calculator provides educational estimates only; always work with a licensed family-law attorney in your state before relying on any number for negotiation or settlement.