How a 529 Plan Grows Tax-Free (and the New Roth IRA Rollover)

A 529 plan is a savings account built for education. You put money in, it gets invested, and it grows. The part that makes it different from an ordinary account is the tax treatment: inside a 529, the growth is not taxed as long as the money is spent on qualified education costs.

The short version: a 529 plan lets your contributions grow tax-free, and qualified withdrawals come out tax-free too, so none of the investment growth is lost to income tax on the way to a school bill.

What a 529 plan is

A 529 plan (named after the section of the tax code that created it) is a state-sponsored, tax-advantaged account for education savings. The mechanics are three steps:

1. Money goes in with after-tax dollars. There is no federal deduction for contributing, though many states offer their own income-tax deduction or credit for residents who use their home-state plan.
2. The balance grows untaxed. Whatever the investments earn (interest, dividends, gains) is never taxed year to year the way a regular brokerage account is.
3. Qualified withdrawals come out tax-free. When the money is spent on eligible education costs, the earnings are free from federal income tax.

A qualified withdrawal is money taken from a 529 and spent on eligible education costs. On those dollars, the investment growth is never taxed.

So the tax break lives entirely in the middle and the end: growth is untaxed while it sits, and untaxed when it comes out for school.

Why tax-free growth adds up

The longer money compounds, the larger the growth portion becomes relative to what you put in, and inside a 529 that entire growth portion escapes income tax. Compounding means earning a return on your past returns, not just on your contributions (see How Compound Growth Works).

Take a steady example: 200 dollars a month for 18 years, invested at a level 6 percent a year. Real returns are never this smooth, but a flat rate keeps the arithmetic clear.

• You contribute about 43,200 dollars over those 18 years (200 dollars times 12 months times 18 years).
• At a level 6 percent it grows to roughly 77,000 dollars.
• That leaves about 34,000 dollars of growth, and in a 529 spent on qualified costs, none of it is taxed.

In a plain taxable account, that growth would face tax along the way or when sold. The 529 wrapper is what keeps the top segment whole.

What counts as a qualified expense

The tax-free treatment is tied to how the money is spent. Qualified education expenses currently include:

• Tuition, fees, books, supplies, and required equipment at eligible colleges, universities, and trade schools.
• Room and board for students enrolled at least half-time.
• Up to 10,000 dollars in student-loan repayment (a lifetime cap, per beneficiary).
• Registered apprenticeship program costs.
• K-12 tuition, subject to an annual per-student limit. That limit is 10,000 dollars per year through 2025 and rises to 20,000 dollars per year starting January 1, 2026.

There is a factual flip side. If money comes out for something that is not a qualified expense, the earnings portion of that withdrawal is taxed as ordinary income and generally carries an additional 10 percent penalty. The contributions portion, already taxed once going in, is not taxed again.

The newer 529-to-Roth-IRA rollover

A long-standing worry about 529 plans is "what if my child does not use it all." A rule that took effect in 2024 gives leftover balances another path: money in a 529 can be rolled into a Roth IRA (a retirement account whose qualified withdrawals are also tax-free) for the same beneficiary.

The mechanics come with conditions:

• The 529 account has to have been open for at least 15 years.
• The lifetime maximum that can be moved this way is 35,000 dollars per beneficiary.
• Each year's rollover counts against the normal Roth IRA contribution limit (7,000 dollars in 2025 for savers under 50), and the beneficiary generally must have earned income at least equal to the amount rolled that year.
• Contributions made in the last five years are not eligible to roll.
• The Roth IRA has to be in the name of the 529 beneficiary, not the account owner.

Within those limits, savings set aside for school that goes unspent can become a head start on retirement, still inside a tax-free wrapper.

On your own timeline

These are the rules and the arithmetic, stated neutrally. How much a 529 grows, how much of that is tax-free growth, and whether any is left to roll into a Roth IRA all depend on your own contributions, time horizon, and the returns you actually see, which only your numbers can answer. VividTimeline models tax-advantaged balances across every year of your plan, so you can watch contributions and untaxed growth build toward a goal like education instead of guessing at it.