Summary: How alimony is calculated depends on your state. Illinois, Texas, Colorado, and New York use statutory formulas or caps; most other states use multi-factor tests weighing marriage length, earning capacity, standard of living, and need versus ability to pay. Formula states produce predictable ranges; factor states produce ranges that depend on the judge. In every state, the inputs that move the number most are the income gap, the length of the marriage, and whether the recipient can become self-supporting.
A minority of states compute guideline support with arithmetic. Illinois is the cleanest: 33.33 percent of the payer's net income minus 25 percent of the recipient's net income, applied when combined income is under $500,000. Two incomes in, one number out, and judges must explain any deviation.
Texas works from a ceiling, not a target: the lesser of $5,000 per month or 20 percent of the payer's gross income. Eligibility is the real gate, most awards require a 10-year marriage plus a qualifying circumstance like disability or family violence. Colorado publishes an advisory formula, 40 percent of the higher income minus 50 percent of the lower, used mainly for temporary orders. New York runs a statutory formula up to an income cap ($228,000), with judicial discretion above it.
Most states give judges a list of factors instead of a formula. The lists rhyme across states: length of the marriage, each spouse's age and health, earning capacity and education, contributions as a homemaker, the marital standard of living, and the recipient's need versus the payer's ability to pay. Some states add fault; most do not.
Factor tests produce ranges, not numbers. Two judges can look at identical facts and differ by hundreds per month, which is why factor-state estimates should always be presented as bands. Attorneys in these states estimate by knowing their judge's tendencies, not by running a formula.
1. The income gap. Alimony exists to bridge the gap between the marital standard of living and what the recipient can earn. A $5,000 monthly gap produces a different case than a $500 gap, under every formula and every factor test.
2. Marriage length. Duration of support tracks duration of marriage almost everywhere. Under 10 years usually means rehabilitative or short-term support; 20-plus years opens the door to long-term awards. Length also affects amount indirectly, because longer marriages correlate with bigger career sacrifices.
3. Self-sufficiency prospects. Courts ask whether the recipient can become self-supporting and how long that takes. A 35-year-old with a degree and work history gets bridge support; a 60-year-old who spent 30 years out of the workforce gets a different analysis. Vocational evaluations sometimes quantify this.
Support ordered during the divorce (pendente lite) often follows a simpler, more formulaic path than the final award. Colorado's advisory formula, California's DissoMaster calculations, and New York's guideline all see heaviest use at the temporary stage, where speed matters more than precision.
Do not anchor on the temporary number. Final orders apply the full factor analysis and frequently differ, sometimes substantially. Treat temporary support as cash flow during the case, not a preview of the outcome.
Even in formula states, judges can deviate. Common deviation grounds: the formula produces an unjust result given the standard of living, one spouse has extraordinary needs (disability, chronic illness), the payer's income is volatile or hard to measure (business owners, commission earners), or the parties' written agreement sets a different number.
Judges must generally state deviation reasons on the record, which creates appealable issues. If your case has a plausible deviation argument in either direction, that is a conversation for counsel, not a calculator.
Use the homepage calculator to get the guideline number for your state approach, then treat it as the center of a negotiation range, not a prediction. In factor states, widen the band: plus or minus 25 percent is a reasonable planning range. Bring the number to an attorney along with your facts; the attorney's job is to tell you where your judge usually lands relative to the guideline.
The estimate's real value is decision support: it tells you whether support is a $500-a-month footnote or a $3,000-a-month centerpiece of the settlement, and that distinction changes your entire negotiation strategy.
Illinois (33.33%/25% guideline), Texas (capped formula), Colorado (advisory 40/50), and New York (formula up to an income cap). Most other states use multi-factor tests instead of formulas.
Marriage length, each spouse's age and health, earning capacity and education, homemaker contributions, marital standard of living, recipient need versus payer ability to pay, and in some states, fault.
No. Even in formula states, judges can deviate for cause and must usually explain the deviation. In factor states there is no formula at all, so estimates are ranges.
Generally yes. The income gap is the single biggest driver of the amount under both formulas and factor tests, because alimony exists to bridge the recipient toward the marital standard of living.
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Data current as of October 2026. Sources: 750 ILCS 5/504; Texas Family Code ch. 8; Colorado advisory maintenance guideline; NY Domestic Relations Law 236B. Legal information only, not legal advice.