Alimony Calculator
Estimate spousal support by state formula, see how TCJA changed alimony tax treatment for post-2018 divorces, and analyze the financial impact on both parties. These are rough estimates only — consult a family law attorney for advice specific to your situation.
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How to Use This Calculator
Support Estimate tab
The default tab. Select your state to apply the appropriate formula (or general estimate), enter the higher earner's income, lower earner's income, and marriage duration. The calculator shows estimated monthly alimony and duration of payments based on your state's guidelines. States like California, New York, Texas, and Illinois have specific formulas; others use judge discretion with general ranges.
Tax Impact (TCJA) tab
This tab shows how the Tax Cuts and Jobs Act changed alimony taxation. For divorces finalized after December 31, 2018, alimony is NOT deductible by the payer and NOT taxable to the recipient. For pre-2019 divorces, the old rules apply: deductible by payer, taxable to recipient. Enter your alimony amount and incomes to see the tax impact for both parties.
Financial Impact tab
Analyze whether a proposed alimony amount is affordable for both parties. Enter both incomes, the proposed monthly alimony, and monthly expenses for each party. The calculator shows post-alimony income, remaining budget after expenses, and percentage of income going to alimony for each side.
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The Formulas
Alimony formulas vary widely by state. Here are the most common approaches:
Duration: half the marriage length (indefinite if >10 years)
New York: Lesser of: (20% payor - 25% payee) or (40% combined - payee income)
Payor income capped at $228,000 for formula
Texas: Max 20% of payor gross or $5,000/month
Duration: 5/7/10 years based on marriage length
Illinois: 33.33% payor net - 25% payee net, capped at 40% combined net
Duration: 20-100% of marriage length
General estimate: 30% of income difference
Duration: marriage length / 3
Many states (Florida, New Jersey) have no formula and rely on judicial discretion considering factors like marriage duration, standard of living, earning capacity, health, and contributions to the marriage.
TCJA Alimony Tax Rules
The Tax Cuts and Jobs Act (TCJA) of 2017 made a major change to alimony taxation, effective for divorces finalized after December 31, 2018:
Post-2018 Divorces (TCJA rules)
Pre-2019 Divorces (old rules)
The OBBBA (One Big Beautiful Bill Act) did NOT change these rules — the TCJA alimony provisions remain permanent. If a pre-2019 divorce agreement is modified after 2018, it continues under the old rules unless the modification expressly adopts the new TCJA treatment.
Example
Sarah & Michael — California, 15-Year Marriage
Michael earns $150,000/year. Sarah earns $50,000/year. They divorce in 2025 (TCJA rules apply). 15-year marriage qualifies as long-term in California.
Support Estimate (California formula)
Tax Impact (TCJA)
Under TCJA, Michael pays the full $35,000 with after-tax dollars. Under the old rules, he would have effectively paid ~$26,600 after the tax deduction. Sarah benefits because she keeps the full amount tax-free.