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Alimony Calculator

Estimate monthly spousal support payments, duration, and total obligation. Three detail levels — from quick estimate to full professional analysis.

All calculations are private — nothing leaves your browser
$
$
years
yrs
yrs
Estimated Monthly Alimony
$1,875–$2,500/mo
Midpoint Estimate$2,188/mo
Annual Alimony$26,250/yr
Income Difference$75,000/yr
Method30–40% of difference
Result copied to clipboard
Advanced Calculator

State-specific formulas, side-by-side comparison, after-tax analysis, and payment timeline with charts.

+ Open Advanced Calculator
Your Situation
$
$
years
Compare With
$2,125/mo
Duration12 yrs
Total$306,000
Method: DissoMaster (Temp): 40% higher − 50% lower
Formula: Temp = 40% × $120K − 50% × $45K
$1,750/mo
Duration4 yrs
Total$84,000
Method: Lower of Formula A or B (cap $228K)
Formula: Min(30%×$120K − 20%×$45K, 40%×combined − payee)
Difference: $375/mo ($222,000 total lifetime difference)
Professional Simulator

Full income breakdown (W-2, self-employment, investments, stock options), what-if scenarios, NPV analysis, and 20-year lifetime wealth projection.

+ Open Professional Simulator
Higher Earner (Payor) — Total: $160,000/yr
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$
$
$
$
$
$
Lower Earner (Payee) — Total: $45,000/yr
$
$
$
$
$
$
$
years
Professional Alimony Analysis
$3,458/mo for 12 years
Payor After-Tax
Gross: $160,000/yr
Federal tax: −$27,743
State tax: −$14,880
SE tax: −$3,532
Alimony: −$41,500
Net: $72,345/yr ($6,029/mo)
Payee After-Tax
Gross: $45,000/yr
Federal tax: −$3,410
State tax: −$4,185
Alimony: +$41,500
Net: $78,906/yr ($6,575/mo)
Lifetime Total$498,000
NPV at 5%$373,918
Payor Effective Rate54.8%
Income Equalization109%

How the Alimony Calculator Works

This alimony calculator uses the most widely applied estimation method in US family courts: the income difference formula. Courts generally award alimony in the range of 30–40% of the gross income gap between spouses, adjusted for marriage length, children, and each state's specific guidelines.

The calculator provides three perspectives: a monthly payment estimate, a projected duration range, and a comparison between rehabilitative (short-term) and durational (longer-term) alimony structures. All figures are estimates — final awards depend on judicial discretion and state law.

Alimony Formula

Monthly Alimony = (Higher Income − Lower Income) × 30–40% ÷ 12 Duration (short marriage <10 yrs) = Marriage Length × 0.4–0.6 years Duration (mid marriage 10–20 yrs) = Marriage Length × 0.5–0.7 years Duration (long marriage 20+ yrs) = Potentially indefinite Total Lifetime Alimony = Monthly Alimony × 12 × Duration Years

The 30–40% range reflects the broad spectrum of how courts weigh the receiving spouse's need and the paying spouse's ability to pay. Higher earners often end up at the lower end (30%) because the payee's need is the primary driver.

Example Calculation

Example: 12-Year Marriage

Higher earner annual income$120,000
Lower earner annual income$45,000
Income difference$75,000/yr
30% of difference$22,500/yr = $1,875/mo
40% of difference$30,000/yr = $2,500/mo
Estimated duration6–8 years
Total lifetime alimony$135,000–$240,000

At the midpoint estimate of $2,188/mo over 7 years, the total alimony obligation would be approximately $183,792. This illustrates why lump-sum settlements are often negotiated.

Frequently Asked Questions

There is no single federal formula for alimony — each state has its own guidelines. The most common approach is the income difference method, where alimony equals 30–40% of the gap between spouses' gross incomes, divided by 12 for a monthly figure. Some states like New York and Illinois have statutory formulas. Judges also weigh factors including standard of living, each spouse's earning capacity, health, and contributions to the marriage.
Duration is generally tied to marriage length. For marriages under 5 years, courts typically award 1–2 years of support. Marriages of 5–10 years may result in alimony lasting 40–60% of the marriage length. Marriages of 10–20 years often produce alimony lasting half or more of the marriage duration. Marriages over 20 years may result in indefinite or permanent support, especially if the recipient cannot become self-supporting.
For divorces finalized after December 31, 2018, alimony is neither deductible by the payor nor taxable to the recipient under the Tax Cuts and Jobs Act (TCJA). For divorces finalized before January 1, 2019, the old rules still apply: the payor deducts alimony, and the recipient pays income tax on it — unless the parties modify the agreement and opt into the new rules.
Yes, in most states alimony can be modified if there is a substantial change in circumstances — such as a significant change in either party's income, the recipient remarrying, the recipient cohabitating with a new partner, or the payor reaching retirement age. The party seeking modification must petition the court and demonstrate the material change. Some agreements include built-in review clauses or automatic termination provisions.
Courts consider many factors including: length of the marriage, each spouse's income and earning capacity, standard of living during the marriage, age and health of both parties, contributions to the marriage (including homemaking and child-rearing), time needed for the receiving spouse to gain education or employment, any marital misconduct (in fault states), and the financial resources of each party including assets divided in the divorce.

Related Calculators

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NY statutory formula with $228,000 income cap for 2026
Alimony Duration Calculator
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Alimony Tax Impact Calculator
Pre-2019 vs post-TCJA tax treatment comparison