By Kevin Luu, Co-Founder and Chief Learning Officer. Reviewed on 2026-09-30.
No. 529 contributions are made with after-tax money: they are not deductible on your federal return, and neither California nor Washington gives a state deduction for them. The tax benefit comes later. Earnings grow without annual tax, and withdrawals used for qualified education expenses are free of federal and California income tax (IRS Publication 970).
That matters more than it sounds for a household earning $750,000 to $3 million. You cannot use a 529 to lower this year’s tax bill, so it belongs after the accounts that do. But the tax-free growth is worth more to you than to most families, because your tax rate on investment gains is among the highest in the country.
Why a 529 is after-tax even when it comes out of your paycheck
Some employers let you send part of each paycheck straight to a 529. That is convenient, but it is still after-tax. The money has already been through federal income tax, Social Security and Medicare, and in California the 1.3% SDI withholding on all wages for 2026 (EDD). A payroll 529 deduction is not like a 401(k) deferral, which comes out before federal income tax.
Many searchers ask whether their state is a “529 parity state”, meaning it gives a deduction for contributions to any state’s plan. For California and Washington families the question does not apply. California allows no deduction for 529 contributions for 2026; a 2025 bill (SB 529) that would have created one died in the Legislature (California Legislature). Washington has no individual income tax in 2026, so there is nothing to deduct against (WA DOR). That also means you are free to pick any state’s plan on cost and investment options alone. Families in states that do offer deductions face a different decision, covered in our guide to whether a 529 is tax deductible in New York.
Which of your accounts actually are pre-tax
If the real goal is to lower this year’s tax, these are the accounts that do it. A 529 comes after them in the order of funding, not instead of them.
| Account (2026) | Goes in | Growth | Comes out | 2026 limit |
|---|---|---|---|---|
| 401(k) or 403(b), traditional deferral | Pre-tax (federal and CA) | Tax-deferred | Taxed as income | $24,500 per employee |
| Dependent care FSA | Pre-tax (federal; see California note below) | n/a (spent within the year) | Tax-free for child care | $7,500 per household |
| 529 plan | After-tax | Tax-free | Tax-free for qualified education | No annual cap; gifts above $19,000 per donor per child use lifetime exclusion |
| UTMA custodial account | After-tax | Taxable to the child (kiddie tax) | Child’s property from the start; child takes control at 18 to 25 | No contribution limit |
| Taxable brokerage | After-tax | Taxable each year | Gains taxed on sale | None |
Sources: 401(k) deferral limit from IRS Notice 2025-67; dependent care FSA limit raised to $7,500 from 2026 by P.L. 119-21 (your employer’s plan must adopt it; California generally does not conform to P.L. 119-21, so the part above the old $5,000 limit may be taxable on your California return); gift tax annual exclusion from Rev. Proc. 2025-32. For a UTMA, the first $1,350 of a child’s unearned income is tax-free for 2026 and income over $2,700 is taxed at the parents’ rate.
Worked example: what “after-tax” costs a $900,000 California household
Assumptions (illustrative): married, filing jointly, $900,000 of combined W-2 pay in San Mateo County, both spouses deferring the full $24,500 to their 401(k)s, two children aged 3 and 6. Federal taxable income lands around $820,000, which is in the 37% bracket (over $768,700 for 2026). California taxable income lands around $840,000, which is in the 10.3% bracket on the 2025 schedule ($742,958 to $891,542; 2026 schedules are not yet published).
Step 1: the pre-tax accounts. Each $24,500 401(k) deferral avoids roughly 47.3% (37% federal plus 10.3% California), about $11,590 per spouse this year. A $7,500 dependent care FSA also comes out before federal income tax (California may tax the part above the old $5,000 limit, since it generally does not conform to the 2025 federal law). These come first.
Step 2: the 529. A $10,000 contribution saves nothing this year. If it were pre-tax, it would save about $4,730. That is the cost of “after-tax”.
Step 3: the growth, where the 529 earns its place. Say the family puts $100,000 into a 529 for the 6-year-old and it earns an assumed 6% a year for 12 years. It grows to about $201,220, of which $101,220 is earnings. Used for qualified college costs, those earnings are never taxed.
The same $100,000 in a taxable brokerage account, sold at the end, would owe at today’s rates roughly 20% federal long-term capital gains tax (taxable income above $613,700 for 2026), 3.8% Net Investment Income Tax and at least 10.3% California tax, since California taxes capital gains as ordinary income. That is about 34.1% of $101,220, or around $34,500, before counting tax on dividends along the way (and somewhat more if the gain pushes California taxable income past $891,542 into the 11.3% bracket on the 2025 schedule). The 529 pays back the missing deduction many times over for a family at this income.
In Washington, the same family would owe about 23.8% federal on the gain (around $24,090). Washington’s 7% capital gains tax applies only to long-term gains above its annual standard deduction ($278,000 for 2025, the latest published), so a single sale this size often owes none. Two cautions for Seattle-area families: long-term gains from selling RSU and ESPP shares count toward that threshold in the same year, and Washington has enacted a 9.9% income tax on AGI over $1,000,000 starting in 2028 (WA DOR). Tax-free growth inside a 529 may matter more for Washington earners after 2028, depending on how the new tax defines income (DOR guidance is still pending).
How much to put in, and whose gift it is
For 2026 each parent can give $19,000 per child without using any lifetime exclusion, so a couple can put $38,000 a year into each child’s 529. A 529 also allows five years of gifts at once: up to $95,000 per donor per child, or $190,000 per child for a couple splitting gifts, reported on Form 709 (Form 709 instructions). Front-loading gives the money the longest time to grow tax-free, which is why it can suit families with young children and a large RSU vest or bonus to place. Our comparison of superfunding versus yearly contributions walks through the trade-offs.
Grandparents can use their own exclusions on top of yours. Gifts above the annual amounts do not trigger gift tax until the lifetime exclusion is used up; they use part of the $15,000,000 per-person lifetime exclusion for 2026 and require a Form 709.
Common mistakes with 529 tax treatment
- Funding the 529 before the 401(k) or dependent care FSA. Pre-tax dollars can save real money now. At this income, the 529 typically takes what is left.
- Assuming every federal expense counts in California. California generally does not conform to the 2025 federal tax law (P.L. 119-21), including its new 529 expense categories (FTB Form 540 booklet). A withdrawal that is qualified federally may be taxable in California. Check before using a 529 for anything other than college.
- Overfunding without a plan. The earnings part of a withdrawal not used for qualified expenses is taxed as income and generally owes an extra 10% federal tax (Pub 970). With two or three children, you can change the beneficiary to a sibling instead. See how 529 ownership and beneficiary changes work.
- Using a UTMA for college money. A UTMA gift is your child’s property from the day it is made, the child takes control at 18 to 25, and its income falls under the kiddie tax. For money meant only for education, a 529 keeps control with you. Our 529 versus custodial account comparison goes deeper.
What to write down for your kids
A 529 is one of the few accounts your children will hear about while they are young. Write one page on why you funded it, what you expect it to cover and what you expect from them in return (a share of costs, a grades standard, a job in summer). When they are old enough to see the statement, they will understand the decision, not just the balance. Conversations fade. Documentation compounds.
Frequently asked questions
Can I deduct 529 contributions on my California return?
No. California has no state deduction or credit for 529 contributions for 2026, whether you use ScholarShare or another state’s plan. A 2025 bill to add one did not pass. The California benefit is tax-free growth and tax-free qualified withdrawals, the same as federal, which is worth a lot at a 10.3% to 13.3% state rate on investment gains (2025 California rates).
If 529s are after-tax, are they still worth it at our income?
Usually yes, for money you expect to spend on education. The higher your tax rate on gains, the more tax-free growth is worth. In the example above, a $100,000 contribution avoids roughly $34,500 of federal and California tax on 12 years of growth. The main risk is overfunding, which you can reduce by spreading savings across children and other accounts.
Your next step
Put your 401(k), dependent care FSA and 529 contributions on one page, in the order above, and check that the pre-tax accounts are full before new 529 money goes in. If you want someone to build that page with you alongside your RSUs and estate documents, our tax management and Age Five Wealth Education work covers it, and the Tax & Wealth Assessment is the place to start.
This is general education, not individual tax advice. The right move depends on your family’s full picture.
Kevin has advised high-income W-2 tech and biotech families since 2015, and leads the education-first Age Five Family Office from Brea, California.
Connect on LinkedIn → · About KevinThis is part of how we approach Age Five Wealth Education for high-income W-2 families at Bright Advisers.
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