Alimony calculator: how courts estimate spousal support

Last updated 2026-07-10

Why isn't there one definitive alimony calculator?

There is no single alimony calculator because every state writes its own rules, and most of them refuse to use a fixed formula. The logic is that a judge should weigh the facts of each marriage instead of plugging numbers into a spreadsheet. Fine in theory. In practice, two couples with identical incomes and identical marriage lengths can walk out of different courtrooms with wildly different support orders.

Child support is different. Every state uses a numeric guideline model for child support, which is why a child support calculator can hand you a defensible number. ^[1] Alimony has no federal mandate to standardize, so states went their own ways.

A few states have inched toward formulas. The American Academy of Matrimonial Lawyers published a suggested formula in 2007: 30% of the paying spouse's gross income minus 20% of the receiving spouse's gross income, capped so the recipient's total income doesn't exceed 40% of the combined gross. ^[2] Some Illinois counties and a handful of other jurisdictions borrowed variations for temporary orders. Most did not.

So when you see an "alimony calculator" online, you're really looking at a tool that runs one of these proposed formulas against your numbers. It's a ballpark, not a verdict. Use it to understand the range. Don't use it to write a settlement.

How does a California alimony calculator work?

A California alimony calculator only works for temporary support, because California explicitly refuses a formula for long-term spousal support. California Family Code §4320 lists 14 factors a court must weigh, including the marketable skills of the supported party, how much that party gave up to build the other spouse's career, and any documented history of domestic violence. ^[3] None of those factors spit out a number on their own.

Temporary support is the kind ordered while the divorce is still pending. For that, California courts do use a formula. Most counties, Los Angeles and San Francisco included, run DissoMaster or similar software that pegs temporary spousal support at roughly 40% of the paying spouse's net monthly income minus 50% of the supported spouse's net monthly income. The exact percentages shift a little by county. ^[4]

Search for an alimony calculator California and you'll find tools built on that temporary-support math. They're accurate for that narrow job. For a final judgment on long-term alimony in California, there is no equivalent formula, and the DissoMaster figure is just a starting line.

Duration is just as open-ended. The rule of thumb, and it's a rule of thumb, not a statute, is that support for a marriage under 10 years runs half the length of the marriage. For marriages over 10 years, the court keeps jurisdiction with no set end date. That 10-year mark dominates California divorce strategy talk, but it's a guideline judges use, not a law forcing their hand. ^[3]

To see how courts treat retirement income and cohabitation, the California Courts self-help center lays out the statutory framework in plain language. ^[4]

For how spousal support fits into your overall filing, the alimony explainer on this site walks through the full picture.

What factors does every state consider when calculating alimony?

Even without a formula, most states pull from the same short list of factors: marriage length, the income gap, standard of living, each spouse's age and health, career contributions, and earning capacity. Here's how the core factors line up across major state frameworks:

Factor	CA (Fam. Code §4320)	FL (§61.08)	TX (Fam. Code §8.052)	AAML Model
Length of marriage	Yes	Yes	Yes	Yes
Income gap between spouses	Yes	Yes	Yes	Yes (primary driver)
Standard of living during marriage	Yes	Yes	Yes	Yes
Age and health of both parties	Yes	Yes	Yes	Yes
Contributions to other spouse's career	Yes	Yes	Yes	Partial
Domestic violence history	Yes	Yes	No explicit factor	No
Marital misconduct / adultery	No (CA is no-fault)	Yes (as a factor)	No	No
Earning capacity / vocational training	Yes	Yes	Yes	Yes

The biggest practical split is marital misconduct. In California, a judge cannot cut support because one spouse had an affair. In Florida, adultery is a statutory factor. ^[5] In Texas, fault can affect the eligibility threshold but not the amount once eligibility is set.

The income gap carries the most weight in every framework. A spouse earning $200,000 a year who was married for 18 years to a spouse earning $40,000 will almost always pay some support. The only real questions are how much and how long.

How is alimony calculated in Florida?

Florida calculates alimony under §61.08, and the state rewrote that section in 2023. Governor DeSantis signed HB 1409 in July 2023, abolishing permanent alimony and replacing it with durational alimony capped at 50% of the marriage length. ^[5] That's a hard ceiling. A 20-year marriage produces at most 10 years of alimony. Marriages under 3 years are presumed to produce none.

The 2023 law also added presumptive amount caps. For marriages under 10 years, the presumptive monthly maximum is 35% of the difference between the parties' net monthly incomes. For 10 to 20 years, it's 40%. For marriages over 20 years, it's 38%. A judge can exceed those caps with written findings, but Florida practitioners now treat them as the starting math. ^[5]

Searching for a Florida child support guidelines calculator next to alimony estimates? The two calculations run separately. Florida child support uses the income shares model under §61.30, and the Florida Department of Revenue posts an official child support guidelines calculator on its site. ^[6] Alimony lives under §61.08. The two numbers don't automatically offset each other, though both hit your net disposable income.

For the official text, the Florida Legislature's online statutes portal carries §61.08 as a stable reference. ^[5]

Alimony and child support calculator: can one tool calculate both?

One tool can spit out both numbers, but only the child support half is reliable. Several tools marketed as an "alimony and child support calculator" try to compute both figures on one screen. Some are genuinely useful. Most blur two very different legal frameworks.

Child support uses a formula in every state, required by federal law under Title IV-D of the Social Security Act. ^[1] That formula is either income shares (used by about 40 states) or percentage of income (used by a smaller group, including Texas for basic support). Once you have both parents' incomes and the custody split, the math is mechanical.

Alimony is discretionary in most states, as covered above. Bundling them into one calculator doesn't sharpen the alimony estimate. You just get a formula-driven child support number sitting next to a directional alimony guess.

The combined tools earn their keep in one scenario: figuring out total cash flow after divorce. If you're the paying spouse and you want your rough monthly obligation, running both together gives you a working budget. Just don't treat the alimony half as anything the court is bound to follow.

For a clean child support calculation on its own, the child support calculator article breaks down each state's model. California has a dedicated tool. The California Department of Child Support Services runs the California Child Support Guideline Calculator, the official state tool for guideline support under Family Code §4055. ^[7] That's the number a judge would use. The alimony figure next to it on any third-party site is not.

If your divorce involves both children and spousal support, the paperwork is where most people stall. The divorce papers guide covers the documents you'll need.

What does the AAML formula actually calculate?

The AAML formula calculates a proposed annual alimony amount from both spouses' gross incomes. The American Academy of Matrimonial Lawyers put it forward in 2007, and it's worth knowing because many online calculators run on it. The formula:

Annual alimony = (0.30 × paying spouse's gross income) minus (0.20 × receiving spouse's gross income)

With a cap: the recipient's total income after support cannot exceed 40% of the combined gross income of both spouses. ^[2]

Example. Paying spouse earns $120,000. Receiving spouse earns $30,000. Combined gross is $150,000, so 40% of that is $60,000. The formula gives (0.30 × $120,000) minus (0.20 × $30,000) = $36,000 minus $6,000 = $30,000 a year. The recipient's total income lands at $30,000 in earnings plus $30,000 in support, which is $60,000, exactly 40% of combined. The cap doesn't bite here.

For duration, the AAML proposal multiplies years of marriage by a factor between 0.3 and 0.5, depending on the length tier. A 15-year marriage at a 0.4 factor produces 6 years of support. ^[2]

This formula gives sane numbers in middle-income marriages. It runs high at very high income levels because it ignores lifestyle sufficiency, which is why many practitioners treat it as a floor rather than a ceiling in high-asset cases.

No state has adopted the AAML formula as binding law. It's influential, not authoritative.

How much is alimony in California typically?

Nobody has clean population-level data on average California alimony awards, because spousal support orders aren't collected in any public database. The best you can do is academic work and practitioner surveys.

A 2020 study in the Journal of Divorce and Remarriage found spousal support was awarded in roughly 10 to 15% of all divorces nationally, down sharply from 25% in the 1960s, with amounts clustered between $400 and $800 a month for median-income households. ^[8] California isn't broken out separately.

What practitioners generally report for California: temporary support orders in Los Angeles County, where one spouse earns $150,000 and the other earns nothing, come out around $4,000 to $5,000 a month on DissoMaster. For final long-term orders in marriages over 15 years with a big income gap, orders in the $2,500 to $6,000 monthly range are common. "Common" here means anecdotally reported, not statistically verified.

Taxes changed the whole equation in 2018. For the receiving spouse, support is no longer taxable income at the federal level, and for the paying spouse it's no longer deductible. The Tax Cuts and Jobs Act of 2017 flipped both rules for divorce agreements signed after December 31, 2018. ^[9] That's a real hit to the paying spouse compared with pre-2018 agreements, and it moves the negotiation.

If you're settling rather than going to trial, the DissoMaster temporary number often becomes the baseline for the whole discussion, even for final support. That's a negotiating reality, not a legal rule.

In an uncontested divorce where you and your spouse already agreed on support, you don't need a court to calculate anything. You write your agreed amount into the marital settlement agreement and the judge approves it. If you're filing on your own, DivorceClear's $149 document packet includes the marital settlement agreement with spousal support provisions already formatted for California courts.

How long does alimony last?

Alimony duration depends on your state and the length of your marriage. Here's the practical breakdown:

Marriage length	CA general practice	FL (post-2023 cap)	TX (maintenance)	AAML model
Under 3 years	Rarely awarded	Presumptively $0	Not eligible	0.3 × years
3-10 years	About half the marriage	Up to 35% of income diff, max 50% of length	Up to 5 years	0.35 × years
10-20 years	Typically half, sometimes longer	Up to 40% of income diff, max 50% of length	Up to 7 years	0.40 × years
Over 20 years	Indefinite jurisdiction	Up to 38% of income diff, max 50% of length	Up to 10 years	0.50 × years

Texas runs a strict eligibility test before duration even matters. Under Texas Family Code §8.051, a spouse must have been married at least 10 years and be unable to meet minimum reasonable needs, unless there's a disability or a child with a disability. ^[10] Texas also caps monthly maintenance at $5,000 or 20% of the paying spouse's gross monthly income, whichever is less. ^[10]

Florida's 2023 reform is the biggest structural change in any major state in recent years. The old "permanent alimony" category, which could run until death or remarriage with no end date, is gone. That matters enormously for long marriages in Florida where one spouse gave up a career. ^[5]

Alimony almost always ends on the recipient's remarriage. Cohabitation is trickier. Many states let the paying spouse petition for modification if the recipient is living with a romantic partner and getting a financial benefit, but that takes court action and proof.

What's the difference between temporary and permanent alimony?

Temporary alimony runs only during the divorce. Permanent alimony was a category that kept the court's jurisdiction open with no automatic end date. They're not two speeds of the same thing.

Temporary alimony (also called pendente lite support) keeps the lower-earning spouse afloat while the case moves through court. Most states calculate it with more mechanical precision because speed matters: judges need a number fast and can't run a full 14-factor analysis at a temporary hearing. California uses DissoMaster for this. Florida judges often use a simplified formula before the 2023 factors get fully argued.

Permanent alimony was never a guarantee of lifetime payment. It meant the court kept ongoing jurisdiction with no built-in end date. Florida just killed it. California still has it in the sense that courts retain jurisdiction over long marriages, but those awards stay open to modification if circumstances change.

Rehabilitative alimony is time-limited and tied to a goal, usually finishing school or getting back into the workforce. A judge might order 3 years of support so a spouse can finish a nursing degree. Most states prefer rehabilitative over permanent support for marriages under 15 years.

Reimbursement alimony pays one spouse back for concrete contributions to the other's career, like funding a medical school education. California lists this as a factor under §4320(b). It's not ongoing support. It's closer to a debt repayment structured as alimony.

Which type applies matters a lot for drafting your settlement. A vague "spousal support" clause with no duration or termination conditions breeds arguments later.

Can you modify or terminate alimony after it's ordered?

Most states let you modify alimony if there's a substantial change in circumstances. The paying spouse loses a job. The recipient lands a big raise. Someone remarries. Health falls apart. The exact standard varies, but "substantial and material change" is the common phrase. ^[11]

Alimony agreed to in a marital settlement agreement can be harder to modify than a judge's order, depending on how the agreement is written. If it says the amount is "non-modifiable," most courts enforce that even after a job loss. That's a real trap people walk into when they trade fixed non-modifiable alimony for a bigger property share.

In California, if the divorce judgment gives the court retained jurisdiction over spousal support, either party can file an Order to Show Cause for modification any time support is still running. If the judgment terminated jurisdiction, common in short marriages, neither party can revive it. ^[3]

Automatic termination events in most states: the recipient remarries, or either party dies. Cohabitation isn't automatic in most states, but it can trigger a modification petition.

The tax angle matters here too. Pre-2019 orders that get modified after 2018 may or may not keep the old tax treatment, depending on whether the modification agreement specifically elects to apply the new rules. The IRS covers this in Publication 504. ^[9]

How do you calculate alimony for an uncontested divorce?

In an uncontested divorce, you and your spouse agree on the alimony amount and duration before filing. The court doesn't calculate it for you. You estimate it with available tools, negotiate a number you both accept, and write it into your marital settlement agreement. The judge checks the agreement for basic fairness and legal compliance, then signs.

Here's a practical way to estimate a reasonable number:

1. Run the AAML formula as a floor. It anchors you to a published methodology. 2. Check your state's temporary support formula if one exists. In California, use the DissoMaster logic (40% of the paying spouse's net minus 50% of the receiving spouse's net). That's your second reference point. 3. Weigh the specific factors in your state's statute. A health issue that limits earning capacity should push the number up. Significant separate property income for the receiving spouse should push it down. 4. Set a duration that matches your marriage length and your state's general practice. 5. Build in termination conditions: remarriage, a specific end date, or cohabitation triggers.

The marital settlement agreement is the key document. It has to spell out the monthly amount, the start date, the end date or termination conditions, the payment method, and whether the amount is modifiable. Leave any of those out and you're building a future dispute.

If you're unsure how to structure those clauses, a divorce attorney consultation (usually $200 to $400 for a document review) can catch problems before you file. That's not the same as hiring a full-service lawyer. You're paying for a review. The divorce attorney article explains when that kind of limited-scope help makes sense.

For couples who've already agreed on every term, including alimony, DivorceClear's document packet includes a state-specific marital settlement agreement at $149 total, formatted to match your court's requirements.

Where can you find free official alimony calculators by state?

There is no official government alimony calculator for any state, because most states don't use a formula. What you can find officially runs to plain-language guides and child support tools.

California: The California Courts self-help center (courts.ca.gov) explains the §4320 factors in plain language and links to county self-help programs. Los Angeles Superior Court's self-help center has staff who answer procedural questions. ^[4]

Florida: The Florida Courts self-help resources (flcourts.org) include guides to the post-2023 alimony reform. The Florida Bar's public education materials explain the new duration caps. ^[5]

Texas: The Texas State Law Library (sll.texas.gov) has a research guide on spousal maintenance with direct links to Family Code §8.051 through §8.059. ^[10]

For child support specifically, the official calculators are:

• California: DCSS Child Support Guideline Calculator at childsup.ca.gov ^[7]
• Florida: Florida Department of Revenue Child Support Calculator at floridarevenue.com ^[6]
• Federal overview: Office of Child Support Services at acf.hhs.gov ^[1]

Third-party tools like Cordell & Cordell's calculator or DivorceSource's calculator run on the AAML formula or state temporary-support formulas. They're fine for ballparking. Cite their methodology openly if you use them in a negotiation.

For how the whole process fits together, the divorce papers guide and the divorce lawyer overview cover the procedural framework you'll be working inside.

Frequently asked questions

Is there an official alimony calculator I can use?

No official government calculator exists for alimony in any state, because most states use judicial discretion rather than a fixed formula. What you'll find online are tools built on the AAML proposed formula or a state's temporary support formula. California's DissoMaster is the closest thing to an official tool, but it's licensed software judges use, not a public website. Use online calculators to understand the range, not as a final figure.

How much alimony will I have to pay in California?

For temporary support in California, the rough formula is 40% of the paying spouse's net monthly income minus 50% of the receiving spouse's net monthly income. Final long-term support depends on 14 factors under Family Code §4320, with no fixed formula. In practice, couples with a big income gap and a marriage over 10 years often see final orders from $2,000 to $6,000 a month, but that's anecdotal, not a guarantee.

How long do you have to be married to get alimony in California?

California has no minimum marriage length for alimony eligibility. For marriages under 10 years, though, courts generally order support for about half the marriage length as a guideline. For marriages over 10 years, courts retain indefinite jurisdiction. A six-month marriage could technically produce a few months of support if circumstances warrant it, but short-marriage alimony awards are rare in practice.

Did Florida eliminate permanent alimony?

Yes. Florida Governor DeSantis signed HB 1409 in July 2023, abolishing the permanent alimony category. Florida now uses durational alimony capped at 50% of the marriage length. A 20-year marriage produces at most 10 years of support. Marriages under 3 years face a presumption against any durational alimony. This is one of the largest structural changes to alimony law in any state in recent years.

How is alimony taxed after the 2018 tax reform?

For divorce agreements signed or modified after December 31, 2018, alimony is no longer deductible by the payer and no longer taxable income to the recipient. This reversal, under the Tax Cuts and Jobs Act, raised the after-tax cost of alimony for paying spouses. Pre-2019 agreements keep the old tax treatment unless both parties agree in writing to apply the new rules during a modification.

Can alimony and child support be calculated together?

Some tools combine both calculations, which helps you estimate total monthly cash flow. Child support uses a mandatory formula in every state. Alimony is discretionary in most states. Running them together doesn't make the alimony number more accurate. It just gives the child support number (formula-driven and reliable) alongside an alimony estimate. The California DCSS guideline calculator handles child support officially. No state has an official combined calculator.

What is the AAML alimony formula?

The American Academy of Matrimonial Lawyers published a model formula in 2007: annual alimony equals 30% of the paying spouse's gross income minus 20% of the receiving spouse's gross income, capped so the recipient's total income doesn't exceed 40% of combined gross. For duration, it multiplies marriage years by a factor of 0.3 to 0.5. No state has adopted it as binding law, but many online calculators and some jurisdictions use it for temporary orders.

Can I modify alimony after the divorce is final?

In most states, yes, if you can show a substantial change in circumstances, such as job loss, a big income change, disability, or the recipient's cohabitation with a new partner. If your marital settlement agreement says the support is non-modifiable, though, courts generally enforce that even after major life changes. California requires the original judgment to retain court jurisdiction. If it terminated jurisdiction, neither party can reopen it.

Does adultery affect alimony in California?

No. California is a pure no-fault state. A judge cannot reduce or eliminate spousal support because one spouse had an affair. Florida is different: §61.08 of the Florida statutes lists adultery as a factor a court may consider. If you're in a fault state and adultery occurred, it may affect the amount or eligibility, so the state-specific rules matter a lot here.

How does alimony work in an uncontested divorce?

In an uncontested divorce, you and your spouse agree on the alimony amount and duration before filing. You write the agreed terms into a marital settlement agreement, the court reviews it for basic compliance, and the judge signs it into a court order. You're not asking the court to calculate anything. Use the AAML formula or your state's temporary support formula as a reference point, then negotiate a number both parties accept.

What's the difference between alimony and spousal support?

They're the same thing. "Alimony" is the older term, still used in most states and in federal tax law. California officially calls it "spousal support" in its statutes. Texas uses "spousal maintenance." The legal concept is identical: post-separation payments from the higher-earning spouse to the lower-earning spouse. Some courts also use "spousal support" to distinguish it from child support administratively.

Is alimony automatic in a long marriage?

No, but the longer the marriage and the larger the income gap, the more likely a court is to award it. In California, a marriage over 10 years triggers indefinite court jurisdiction over support, but that doesn't mean support is automatically ordered. A spouse who earned high income throughout the marriage and has strong post-divorce earning capacity may get little or no support even after a 20-year marriage, depending on the §4320 factors.

How much does Texas cap spousal maintenance at?

Texas Family Code §8.054 caps monthly spousal maintenance at the lesser of $5,000 or 20% of the paying spouse's average gross monthly income. Texas also requires the receiving spouse to be unable to meet minimum reasonable needs and generally requires a 10-year marriage for eligibility, with exceptions for disability or domestic violence. Texas is one of the more restrictive states on alimony eligibility and amount.

Sources

1. U.S. Department of Health and Human Services, Office of Child Support Services: Federal law under Title IV-D of the Social Security Act requires every state to use a numeric child support guideline formula.
2. American Academy of Matrimonial Lawyers, Proposed Formula for Alimony (2007): AAML proposed formula: 30% of paying spouse's gross income minus 20% of receiving spouse's gross income, capped at 40% of combined gross for the recipient's total income.
3. California Legislative Information, Family Code §4320: California Family Code §4320 lists 14 factors for spousal support and establishes that courts retain jurisdiction over long marriages.
4. California Courts Self-Help Center, Spousal or Partner Support: California courts use DissoMaster software for temporary support calculations, and the California Courts self-help center explains the §4320 framework.
5. Florida Legislature, Florida Statutes §61.08 (as amended by HB 1409, 2023): Florida HB 1409 signed July 2023 abolished permanent alimony and capped durational alimony at 50% of the marriage length, with presumptive amount caps of 35-40% of income difference.
6. Florida Department of Revenue, Child Support Guidelines: Florida Department of Revenue provides the official child support guidelines calculator under §61.30.
7. California Department of Child Support Services, Child Support Guideline Calculator: The California DCSS runs the official Child Support Guideline Calculator for guideline support under Family Code §4055.
8. Journal of Divorce and Remarriage, spousal support award rate study (2020): Spousal support was awarded in roughly 10-15% of all divorces nationally as of 2020, down from 25% in the 1960s, with amounts clustered between $400 and $800 per month for median-income households.
9. IRS Publication 504, Divorced or Separated Individuals: The Tax Cuts and Jobs Act of 2017 eliminated the alimony deduction for payers and the taxable income rule for recipients for agreements signed after December 31, 2018.
10. Texas Family Code §8.051-§8.054 via Texas State Law Library: Texas caps monthly spousal maintenance at the lesser of $5,000 or 20% of the paying spouse's average gross monthly income, and generally requires a 10-year marriage for eligibility.
11. Uniform Law Commission, Uniform Marriage and Divorce Act: The 'substantial change in circumstances' standard for alimony modification is reflected in the Uniform Marriage and Divorce Act and adopted in most state statutes.