Alimony / spousal support calculator

How alimony is calculated in the United States

Unlike child support, there is no federally mandated framework for alimony. Each state handles it differently, and within every state, the statute either gives the judge a formula (Massachusetts, Pennsylvania, Texas, Illinois for short-term marriages) or a long list of factors (New York, California, Florida, most of the South) that the judge weighs. The result is that two similar couples can get very different awards depending on the state — and even within the same state, depending on the judge.

The formulas judges and mediators actually use

Even in discretionary states, lawyers and mediators almost always start with a formula. The most common are:

• AAML formula: 30% of the payor's gross income minus 20% of the payee's gross, capped so the payee doesn't end up with more than 40% of the payor's income post-support.
• Massachusetts general-term: 30–35% of the income gap, duration scaled to marriage length (50% for <5 years, 80% for 15–20 years, indefinite for >20 years).
• Pennsylvania / New Jersey COLTS: 40% of the payor minus 50% of the payee, generally for half the duration of the marriage.
• Texas maintenance: 20% of the payor's gross OR $5,000/month, whichever is less — and only if the marriage lasted 10+ years or the payee has a disability.

Worked example: AAML formula

Higher earner makes $10,000/month. Lower earner makes $3,000/month. Marriage lasted 12 years.

• Monthly: 30% × $10,000 − 20% × $3,000 = $3,000 − $600 = $2,400
• Cap check: 40% × $10,000 = $4,000 → $2,400 is under the cap, so it stands.
• Duration: graduated multiplier at 12 years ≈ 0.5 × marriage length = 72 months.
• Total over life of order: $2,400 × 72 ≈ $172,800.

What the formula leaves out

Judges routinely deviate from formula numbers for substantive reasons:

• Imputed income: if a spouse voluntarily reduced earning (quit a job, took a lower-paying role) the court can impute what they'd earn at capacity.
• Lifestyle: the marital standard of living is an explicit factor in almost every state — a stay-at-home spouse in a long, high-income marriage often gets support well above a bare-formula output.
• Fault: a minority of states still allow adultery or domestic abuse to affect alimony, either barring support for the at-fault spouse or increasing it for the victim.
• Property division: if one spouse walks away with a large, income-producing asset, courts may reduce alimony to reflect the imputed income from that asset.
• Age, health, education: a 55-year-old stay-at-home spouse who hasn't worked in 20 years will almost always get more than a 35-year-old with a nursing degree.

Modification and termination

Most alimony orders are modifiable for a substantial, continuing change in circumstance — job loss, serious illness, retirement, the recipient's remarriage or cohabitation. A growing number of states impose automatic termination at the payor's normal retirement age. Permanent or indefinite orders are still the default output of many long-marriage formulas, but those terms don't mean truly forever — they mean "until something legally significant changes."

Before you rely on this estimator

Use this for early conversations — prenup discussion, mediation prep, back-of-the-envelope before talking to a lawyer. The formulas above are the most common ones in use, but your state may not use any of them, or may use them only advisorily. Before any filing or agreement, run the real numbers with a family-law attorney licensed in your state and check whether your agreement date lands before or after the 2018 tax change that eliminated the alimony deduction.