Alimony and Spousal Support Estimator
Rough monthly spousal support estimate from the income gap, length of marriage and children.
What does the undefined do?
It gives a rough monthly spousal support figure based on the gap between the two incomes, scaled by the length of the marriage and whether children are involved.
- Inputs: both monthly incomes, the number of years married and the number of children.
- Output: an estimated monthly support figure and a suggested duration.
- Method: a share of the income gap that grows with the marriage length, plus a small uplift for children, capped at 40 percent of payer income.
Quick answer
A ten-year marriage with a monthly income gap of 4,000 and no children comes out near 1,600 a month, with a suggested duration of about four years. Every jurisdiction differs.
What This Calculator Really Does
Spousal support has no single formula, but most guidelines start from the same idea: the greater the income gap and the longer the marriage, the more support is due. This tool applies a rate to the income gap that rises from about 20 percent for a short marriage to 40 percent after fifteen years, adds a small uplift when there are children, and caps the result at 40 percent of the payer net-style income as a reasonableness check. It also suggests a duration of roughly 40 percent of the marriage length. Real awards depend on the jurisdiction, the standard of living during the marriage, both parties needs and earning capacity, and any child support that runs separately.
The formula it uses
Monthly support = (payer income minus recipient income) x (0.2 + 0.02 x min(years, 15)) x (1.1 if children else 1), capped at 0.4 x payer income. Suggested duration = 0.4 x min(years, 15).
Worked example with real numbers
A ten-year marriage with the higher earner on 6,000 a month and the lower earner on 2,000. The gap is 4,000, the rate after ten years is 0.4, so the estimate is 1,600 a month, below the 2,400 cap. The suggested duration is about four years.
Common mistakes to avoid
- Confusing alimony with child support, which is calculated separately and on different rules.
- Forgetting that support is usually taxable or deductible depending on jurisdiction and tax law.
- Assuming a single lump sum and a monthly payment are interchangeable, when the present values differ.
Assumptions and limitations
Incomes are treated as stable and net of nothing in particular, since jurisdictions differ on whether they use gross or net. Child support is not included. The formula is a rough guideline, not a legal calculation.
Disclaimer
This is a rough estimate and educational only, not legal or tax advice. Spousal support rules vary enormously by jurisdiction and by the facts of each case, so consult a qualified family lawyer before relying on any figure.
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Frequently Asked Questions
How is the undefined calculated?
The income gap is multiplied by a rate that grows with the marriage length, adjusted slightly for children, then capped at 40 percent of the payer income. The steps panel shows each figure.
What do I need to use the undefined?
Both monthly incomes, the number of years married and the number of children. Everything else is built in.
What does the result from the undefined show?
An estimated monthly support figure and a suggested duration, with the income gap behind it.
How long does alimony usually last?
It varies widely, from a few years for a short marriage to long or indefinite terms for long marriages. This tool suggests roughly 40 percent of the marriage length as a starting point.
Is alimony the same as child support?
No. Child support is for the children and generally has set guidelines, while spousal support is for the former partner and depends on the marriage and the income gap.
Is the undefined really free?
Yes — 100 percent free, no sign-up, and everything runs in your browser.
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