Alimony Calculator

Estimate spousal support amount and duration based on income difference and years of marriage.

By Konstantin Iakovlev · Updated September 2026 · Source: IRS — Topic No. 452, Alimony

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Monthly Alimony

$1,750.00

Annual Alimony

$21,000.00

Est. Duration

Medium-term: ~6.0 years

Alimony Calculation

Higher Earner Income$120,000.00
Lower Earner Income$45,000.00
Combined Income$165,000.00
30% of Higher Income − 20% of Lower Income$27,000.00
Cap: 40% of Combined Income − Lower Income$21,000.00
Monthly Alimony$1,750.00
Annual Alimony$21,000.00

Duration & Total Estimate

Years Married12
Estimated DurationMedium-term: ~6.0 years
Total Estimated Alimony$126,000.00

The 40% cap applies: the formula amount would leave the lower earner with more than 40% of combined income, so the lower figure is used.

Tax Note: Since 2019 (Tax Cuts and Jobs Act), alimony payments are not tax-deductible for the payer and not taxable income for the recipient for agreements executed after December 31, 2018.

Use the Alimony Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only and does not constitute legal advice. Results are estimates based on the information you provide and the rules described on this page. Consult an attorney licensed in your state for advice specific to your situation.

How It Works

Spousal support hinges largely on the income gap between divorcing partners and how long the marriage lasted. Feeding those two inputs into the estimate below produces a ballpark figure for both the monthly amount and how long payments might run, giving each side a concrete starting number to weigh before settlement talks get underway.

By default the estimate uses the guideline of the American Academy of Matrimonial Lawyers (AAML): 30% of the higher earner's gross income minus 20% of the lower earner's gross income, capped so that the lower earner's income plus alimony does not exceed 40% of the couple's combined gross income. The cap takes over whenever the lower earner makes more than a quarter of what the higher earner makes. You can switch to a flat 30%, 33% or 40% of the income difference instead, closer to how some states frame it; Massachusetts, for example, generally limits alimony to 30–35% of the difference in gross incomes. Duration follows a common rule of thumb: about a third of the marriage length for marriages under 10 years, about half for 10 to 20 years, and possibly no fixed end date after 20 years.

No estimate carries the force of a court order, so read this as an opening position rather than a settled obligation. The formula also says nothing about the non-financial trade-offs a marriage often involves, such as one partner stepping back from a career to raise children or support the other's work. A family law attorney can fold those circumstances into advice tailored to your situation.

Example: 15-Year Marriage, Income Disparity

  1. 1 Input: Higher earner = $120,000/year, lower earner = $40,000/year, years of marriage = 15, formula = AAML guideline.
  2. 2 Formula: (30% of $120,000) − (20% of $40,000) = $36,000 − $8,000 = $28,000. Cap: 40% of the $160,000 combined income is $64,000, minus the lower earner's $40,000 = $24,000. The lower figure applies, so alimony is $24,000 a year.
  3. 3 Result: $2,000 per month. A 15-year marriage falls in the 10–20-year band, so duration is about half its length, 7.5 years (90 months), for an estimated total of $180,000.
  4. 4 Context: Without the cap the lower earner would end up with $40,000 + $28,000 = $68,000, or 42.5% of the $160,000 combined income. The estimate doesn't account for child support, health insurance or other factors a court might weigh, such as a substantial inheritance received by one spouse during the marriage.

Source: IRS — Topic No. 452, Alimony · Last updated: September 2026

Frequently Asked Questions

How is alimony calculated?
There is no single federal formula. Most states consider length of marriage, income disparity, standard of living during marriage, each spouse's earning capacity, age and health, and contributions to the marriage (including homemaking). Some states use guideline formulas. This calculator starts from the AAML guideline, 30% of the payer's gross income minus 20% of the recipient's, capped so the recipient ends up with no more than 40% of combined gross income, and also offers flat percentages of the income difference.
Is alimony taxable in 2026?
For divorce or separation agreements executed after December 31, 2018, alimony is not deductible by the payer and not taxable income for the recipient. Agreements executed before 2019 keep the old rules (deductible by the payer, taxable to the recipient); a later modification moves them to the new rules only if it expressly says that the repeal of the deduction applies.
How long does alimony last?
Duration depends on marriage length and state law. This calculator uses a common rule of thumb: about a third of the marriage length for marriages under 10 years, about half for 10 to 20 years, and possibly indefinite support after 20 years. States differ: California, for example, generally treats half the length of a marriage under 10 years as a reasonable period. Many states are moving toward rehabilitative (time-limited) alimony.

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