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Washington Alimony Calculator (2026)

Washington’s RCW 26.09.090 provides no fixed alimony formula—courts weigh a list of factors when ordering spousal maintenance. Because the statute is silent on a numeric rule, practitioners often use the American Academy of Matrimonial Lawyers guideline: 30% of the higher earner’s gross income minus 20% of the lower earner’s gross income, capped so the recipient’s total income does not exceed 40% of the combined income, with a duration based on marriage length. This calculator gives only an estimate, not a legal determination.

Reviewed 2026-09-02 · Estimates only — not legal or financial advice.

Washington has no statutory alimony formula. Courts decide case by case under RCW 26.09.090. The calculator below shows a widely used rule of thumb (the AAML guideline) as a negotiation starting point — it is not the law and a judge may land anywhere the factors justify.
Before taxes.
Before taxes.
The law behind this calculator: Washington spousal maintenance factors — RCW 26.09.090.

How Washington calculates it

  • Take 30% of the higher‑earning spouse’s annual gross income.
  • Take 20% of the lower‑earning spouse’s annual gross income.
  • Subtract the lower‑earner amount from the higher‑earner amount.
  • If the resulting support would raise the recipient’s total income above 40% of the couple’s combined income, reduce it to meet that cap.
  • Apply the duration rule‑of‑thumb: 30% of marriage length if under 3 years, 50% if 3–10 years, 75% if 10–20 years, and indefinite if over 20 years.

Worked example

In the worked example, the higher earner makes $100,000 per year and the lower earner $40,000. Applying the rule‑of‑thumb, 30% of $100,000 is $30,000 and 20% of $40,000 is $8,000, giving a difference of $22,000 per year. The 40% cap reduces this to $16,000 per year, or roughly $1,333 per month. For a 12‑year marriage, the duration guide (10–20 years bracket) suggests 75% of 144 months, about 108 months of support. The court is not bound by these numbers.

Frequently asked questions

How does Washington calculate spousal maintenance without a statutory formula?

Washington courts apply the factors listed in RCW 26.09.090. Practitioners often start with the 30%‑minus‑20% guideline as a benchmark, then adjust for the 40% income cap and the marriage‑length duration guide.

Is spousal maintenance taxable in Washington?

Washington does not have a state income tax, so alimony is not subject to state tax. For federal purposes, the Tax Cuts and Jobs Act of 2017 eliminated the deduction for payers and the inclusion for recipients for agreements executed after December 31 2019.

How long does maintenance typically last in Washington?

A common informal benchmark is one year of maintenance for every three to four years of marriage, but the rule‑of‑thumb used here suggests 75% of the marriage length for marriages between 10 and 20 years, which for a 12‑year marriage yields about 108 months.

Can I receive partial maintenance if my post‑divorce income is low?

Yes. The 40% cap ensures the recipient’s total income does not exceed 40% of the combined income, so the amount can be reduced to reflect the recipient’s own earnings while still providing support.

What recent changes affect Washington spousal maintenance?

The primary change is that Washington still has no statutory formula; the recent shift is the federal tax treatment change in 2020, which removed the alimony deduction for payers and the taxable inclusion for recipients.

Is the calculation different in Seattle, Spokane or Tacoma?

No. RCW 26.09.090 applies statewide, so courts in Seattle, Spokane, Tacoma and every other county start from the same guideline. Local practice can differ in how judges weigh deviation factors and in typical negotiated outcomes, but the formula on this page is the one used across Washington.

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