Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Estimated monthly support
$1,900
Estimated duration
4.0 years
Rough lifetime total (est. duration)
$91,200
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter length of marriage (years).
- 2Enter paying spouse monthly gross income ($).
- 3Enter receiving spouse monthly gross income ($).
- 4Read your estimated monthly support on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
States that use a formula rather than pure judicial discretion for spousal support typically tie duration to marriage length: a common approach (similar to guidelines used in states like Texas and approximated by many others informally) awards roughly 1 year of support per 3 years of marriage for shorter marriages, with marriages over 20 years often eligible for indefinite or long-term support subject to review. For amount, a widely referenced (though not universal) approximation is 30-35% of the paying spouse's gross income minus 20% of the receiving spouse's gross income, capped so total support doesn't exceed 40-50% of the paying spouse's income. This calculator applies that duration and amount logic to give a starting estimate, but actual awards vary enormously by state, judge discretion, marital standard of living, and whether the state uses guidelines at all versus pure case-by-case judicial discretion.
Worked example
Using the values the calculator loads with:
Inputs
- Length of marriage: 12 years
- Paying spouse monthly gross income: 8000 $
- Receiving spouse monthly gross income: 2500 $
Results
- Estimated monthly support: $1,900
- Estimated duration: 4.0 years
- Rough lifetime total (est. duration): $91,200
What each field means
Inputs
- Length of marriage (years)
- The length of marriage used in the calculation, measured in years. Starts at 12 years so you have a working example on load.
- Paying spouse monthly gross income ($)
- The paying spouse monthly gross income used in the calculation, measured in $. Starts at 8000 $ so you have a working example on load.
- Receiving spouse monthly gross income ($)
- The receiving spouse monthly gross income used in the calculation, measured in $. Starts at 2500 $ so you have a working example on load.
Results
- Estimated monthly support
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Estimated duration
- Returned as a plain value. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Rough lifetime total (est. duration)
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Do all states use a formula for alimony?
No, many states leave duration and amount entirely to judicial discretion based on factors like standard of living, age, health, earning capacity, and contributions to the marriage, without any numeric formula at all. Formula-based approaches are more common for setting a starting negotiation point than a guaranteed court outcome.
Why does a 20+ year marriage often mean indefinite support?
Courts recognize that a spouse who was out of the workforce or in a supporting role for two decades or more faces a much steeper path back to self-sufficiency, and many states allow permanent or indefinite support (still modifiable later) specifically for these longer marriages rather than a fixed end date.
Does alimony change if the recipient remarries?
In most states, yes, remarriage automatically terminates alimony obligations since the support was tied to the marital relationship, though some states require the recipient to prove cohabitation with a new partner rather than remarriage specifically. Check your state's statute and your specific settlement agreement's terms.
Is alimony taxable?
For divorces finalized after December 31, 2018, alimony is no longer tax-deductible for the payor or taxable income for the recipient under federal law, a major change from the pre-2019 rules. Divorces finalized before that date generally still follow the old tax treatment unless the agreement was later modified to adopt the new rules.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Child Support Guideline Range Calculator
Estimate a rough child support range using an income-shares style guideline.
Estate Executor Fee Calculator
Estimate the executor's fee for administering an estate under state statutory schedules.
Immigration Sponsor Income Requirement Calculator (125% FPL)
Check if your household income meets the 125% federal poverty guideline for sponsoring an immigrant.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Alimony Duration Guideline Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/alimony-duration-guideline
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/alimony-duration-guideline" target="_blank" rel="noopener">Alimony Duration Guideline Calculator — RevenueLab</a> (2026).</p>
Source: [Alimony Duration Guideline Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/alimony-duration-guideline) (2026).