A 529 plan grows tax-free for education, but the plan only works if the deposits are sized against a bill that inflates faster than most prices. This calculator projects your balance the year your child enrolls, projects the four-year cost of college in those same future dollars, and tells you the coverage share, the gap, and the monthly deposit that closes it.
College savings questions usually get answered with rules of thumb, and the rules of thumb disagree. This page replaces them with two projections made in the same future dollars. One side grows your account: the balance you have today compounds at your expected return while each monthly deposit adds to it. The other side grows the bill: today's one-year cost of attendance compounds at education inflation, once for each year of enrollment. The difference between the two, measured the month your child starts college, is the number every 529 conversation should start from.
The calculator reports a coverage share rather than a pass-fail verdict on purpose. Fully funding a projected sticker bill is one planning target among several, and rarely the most sensible one, because sticker price overstates what most families actually pay. The later section on net price puts numbers on that gap.
Variables in plain terms. B0 is your current balance and M is the monthly contribution, deposited at month end. r is the expected annual return, which converts to a monthly rate i through the geometric mean, the same convention used elsewhere on this site, and n is the number of monthly deposits before enrollment. Y is the years until enrollment. C is today's published one-year cost and g is college cost inflation, so the first year of college costs C grown for Y years and each later year adds one more turn of the crank.
The required-monthly line deserves one sentence of explanation. Because the four bills arrive in the future, the money sitting in the account in year two or three keeps growing, so the true funding target is the discounted value of all four bills at enrollment, not their raw sum. Dividing what remains after your current balance has compounded by the future value factor of a dollar a month gives the deposit that lands exactly on that target.
Start with $15,000 saved, add $400 a month, and give the account ten years at a 6 percent blended return. The balance at enrollment reaches $91,852.09, of which $26,862.72 is growth on the money you already had and $64,989.38 is what the monthly deposits and their earnings built. Meanwhile the bill: the average published budget for an in-state student at a public four-year college is $30,990 this year per College Board, and at 5 percent inflation the first year of college costs $50,479.44 ten years out. All four years together total $217,572.72.
| Result at the defaults | Amount |
|---|---|
| Projected balance at enrollment | $91,852.09 |
| Growth on today's $15,000 | $26,862.72 |
| Built by $400 monthly deposits | $64,989.38 |
| Projected first-year cost | $50,479.44 |
| Projected four-year total | $217,572.72 |
| Coverage share of the bill | 46.1% |
| Required monthly to fully fund | $1,059.96 |
The year-by-year view shows what a 46 percent coverage share feels like. The account pays the entire $50,479.44 freshman bill and finishes with $43,855.01, which covers most but not all of sophomore year: it runs dry with $9,148.41 of that year still unpaid, leaving $114,089.86 of junior and senior year to fund from income, aid, or borrowing. That is the honest reading of a typical savings effort against a full sticker bill, and it is why the next two sections matter more than the gap itself.
The deposit size moves the balance almost linearly, so every extra $100 a month buys roughly the same slice of the bill. Starting earlier works differently: it compounds, because each year of head start gives every prior dollar another turn of growth and shrinks the target by removing one year of inflation. At the default assumptions, the full-funding deposit is $659.69 a month for a newborn, $852.69 for a five-year-old, and $1,059.96 at the ten-year default horizon. The same $400 a month that covers 46.1 percent starting at age 8 would have built $195,198.85 from birth, covering 66.4 percent of that child's larger bill on this calculator's basis.
| Monthly contribution | Balance at enrollment | Share of the bill |
|---|---|---|
| $300 | $75,604.75 | 38.0% |
| $400 | $91,852.09 | 46.1% |
| $500 | $108,099.44 | 54.3% |
| $600 | $124,346.78 | 62.5% |
| $800 | $156,841.47 | 78.8% |
Return assumptions move the outcome too, but less than intuition suggests. At 4 percent the default plan reaches $80,882.03 (39.5 percent coverage); at 8 percent, $104,433.58 (53.9 percent). Compare that spread with the inflation lever: at 3 percent college inflation the four-year bill totals $174,239.57 and full funding needs $817.30 a month, while at 7 percent it swells to $270,667.90 and needs $1,356.89. Cost inflation is the variable you cannot invest your way out of, which is why the school choice matters so much. Switching the target from the in-state public budget of $30,990 to the $50,920 out-of-state budget raises the required monthly to $1,847.96, and the $65,470 private-nonprofit budget raises it to $2,423.25.
One more projection worth seeing, because it catches even engaged families off guard. A grandparent superfunds the account at birth with the maximum five-year election of $95,000. At a 6 percent return that grows to $271,162.22 by year eighteen, an enormous balance by any ordinary standard. The projected sticker bill for that child's four years is $321,453.99, and its discounted value at enrollment is $294,129.44. Even the superfunding election finishes $22,967.22 short of full coverage at these assumptions. The lesson is that fully funding sticker price is a stretch target for nearly everyone, which is exactly why the next section matters.
The College Board's Trends in College Pricing and Student Aid 2025 report puts the 2025-26 average published tuition and fees at $11,950 for in-state students at public four-year colleges, inside a $30,990 full budget. But the same report shows first-time full-time students at public four-year schools received enough grant aid to cut average net tuition and fees to an estimated $2,300, and 79 percent of them received some federal, state, or institutional grant aid. Average published prices rose 2.9 percent this year, the slowest stretch in decades, and inflation-adjusted net tuition at public four-year colleges has actually fallen from its 2012-13 peak.
The practical translation: aim your 529 at a share of the bill, not the whole thing. Covering half to two-thirds of the projected cost from savings, with current income and scholarships carrying the rest, is a common and defensible target. The calculator's coverage share tells you where you stand; run the same numbers with the savings goal calculator if you prefer to work from a target amount backward to a deposit. And because the bill is denominated in inflated dollars, the inflation calculator shows what any future cost means in today's money.
The federal tax treatment has not changed: no deduction going in, tax-free growth, and tax-free withdrawals for qualified education expenses. What changed for tax year 2026 is scope. The One Big Beautiful Bill Act doubled the annual K-12 withdrawal cap from $10,000 to $20,000 per beneficiary and expanded qualifying K-12 spending beyond tuition to curriculum materials, tutoring, standardized testing fees, and therapies for students with disabilities. It also added postsecondary credentialing programs, trade licenses, and certification exam costs to the qualified list, which quietly turns a 529 into a career-change account, not just a college account.
The overfunding exits have widened too. Up to $35,000 of a 529 can roll into the beneficiary's Roth IRA over time under SECURE 2.0, provided the account has been open at least 15 years and each year's rollover fits inside the annual Roth limit, $7,500 in 2026. Up to $10,000 lifetime can repay student loans, and unused balances can jump to a sibling, cousin, or eventually the beneficiary's own children with no tax consequences.
On the contribution side, there is no federal cap; the effective limits are the gift tax rules and each state plan's aggregate ceiling, which ranges from roughly $235,000 to $675,000. The 2026 annual gift exclusion is $19,000 per donor per beneficiary under IRS Rev. Proc. 2025-32, and the five-year superfunding election lets one donor front-load $95,000, or $190,000 for a married couple, with an election on Form 709. More than 30 states add a state deduction or credit on the way in, which makes the after-tax math even friendlier than the federal-only picture. Non-qualified withdrawals still cost the earnings portion ordinary income tax plus a 10 percent penalty, with the penalty waived for scholarships, military academies, death, or disability.
The growth mechanics behind any of these projections are the same ones in the compound interest calculator; the 529 simply removes the tax drag from the compounding. The FAFSA opens each fall, typically around October 1, and a parent-owned 529 is assessed at no more than 5.64 percent of its value against need-based aid, while grandparent-owned plans escaped the income trap entirely under the simplified FAFSA.
It depends almost entirely on when you start. At this calculator's assumptions (a $30,990 public four-year budget today inflating at 5 percent, a 6 percent return), fully covering the projected sticker bill takes about $659.69 a month if you start at birth, $852.69 at age 5, and $1,059.96 by age 8. Those are full-funding numbers, and most families should not chase them: after grant aid, the average net tuition and fees paid by first-time in-state students at public four-year colleges was an estimated $2,300 in 2025-26 per College Board data. A common approach is covering half to two-thirds from savings and letting current income, aid, and scholarships carry the rest.
You have more exits than most people realize. You can change the beneficiary to another family member, including yourself, with no tax or penalty. Under SECURE 2.0, up to $35,000 of the balance can roll into the beneficiary's Roth IRA over time, provided the account has been open at least 15 years and each year's rollover fits inside the annual Roth contribution limit ($7,500 in 2026). Up to $10,000 lifetime can repay student loans. Non-qualified withdrawals are taxed only on the earnings portion, as ordinary income plus a 10 percent penalty, with the penalty waived for scholarships, attendance at a military academy, death, or disability of the beneficiary; your original contributions always come out tax-free.
Not on your federal return: there is no federal deduction for contributing. More than 30 states offer a state income tax deduction or credit, most requiring you to use your own state's plan, and a few states offer tax parity for any state's plan. The federal benefit is on the other end: growth is tax-deferred and qualified withdrawals are entirely tax-free, so no federal tax is ever due on the earnings used for education. Watch one trap: several states claw back prior deductions if you roll the balance to another state's plan.
There is no federal annual contribution cap. The practical limits come from three places. First, gift tax: contributions are completed gifts, and the 2026 annual exclusion is $19,000 per donor per beneficiary (Rev. Proc. 2025-32), doubled to $38,000 for a married couple. The five-year superfunding election stretches this to $95,000 per donor, $190,000 per couple, in a single year with a Form 709. Second, each state plan sets an aggregate account ceiling, ranging from roughly $235,000 to $675,000 depending on the state. Third, beginning in tax year 2026, the One Big Beautiful Bill Act raised the K-12 withdrawal cap to $20,000 per beneficiary per year and expanded the qualifying K-12 expenses beyond tuition.
Less than most savings, and grandparent-owned plans barely count at all. A parent-owned 529 is a parental asset on the FAFSA, assessed at no more than 5.64 percent of its value against need-based aid, far gentler than the 20 percent assessment on student-owned assets. Since the simplified FAFSA took effect with the 2024-25 cycle, distributions from a grandparent-owned 529 no longer count as student income, which removed the old trap where grandparent generosity cut the aid package. The FAFSA opens each fall, typically around October 1, and filing early improves your odds on state and school aid that is handed out first come, first served.
Use a rate that falls as enrollment approaches, because most age-based portfolios shift from equities toward bonds and cash in the final years. A blended 6 percent is a reasonable single-number assumption for a child around age 8. The calculator defaults show what that rate is worth: at 4 percent the default plan reaches $80,882.03 by enrollment, covering 39.5 percent of the projected bill; at 6 percent it reaches $91,852.09, or 46.1 percent; at 8 percent, $104,433.58, or 53.9 percent. The spread between those outcomes is smaller than the spread between starting at birth and starting at age 8, which is the point: time in the account matters more than the return you pick.