Calculatrice de plan 529

529 Plan Calculator

A 529 plan is the most tax-efficient way to save for college. Contributions grow tax-deferred, and withdrawals for qualified education expenses — tuition, room and board, books, and computers — are completely tax-free at the federal level. More than 30 states also offer an income tax deduction or credit for contributions, making the 529 one of the few savings accounts that gives you an immediate return in the year you contribute. This calculator shows whether your monthly contributions are on pace to cover projected college costs and how much tax-free growth your account will earn by the time your child enrolls.

How 529 Plan Growth Is Calculated

529 plan growth uses the standard future value formula with regular contributions:

FV = PV(1 + r)^n + PMT x [(1 + r)^n - 1] / r

Where PV is the current balance, PMT is the monthly contribution, r is the monthly return rate (annual rate / 12), and n is the number of months until the child starts college (typically at age 18). Because 529 earnings are never taxed on qualified withdrawals, the full compound growth flows to your family. In a taxable savings account, dividends and capital gains reduce the effective compounding each year — on an $80,000 taxable account earning 7%, you might lose $3,000-$5,000 to taxes over 10 years that the 529 keeps working for you.

Worked Examples

Scenario 1 — Newborn, $300/month: James and Lisa open a 529 the week their daughter is born. They contribute $300/month for 18 years at a 7% return. Total contributed: $64,800. Projected balance at college enrollment: $129,992. Tax-free growth: $65,192. In a taxable account at 15% capital gains, they would owe roughly $9,800 on those gains.

Scenario 2 — Age 5, $600/month: Marcus starts a 529 when his son is 5. He contributes $600/month for 13 years at 7%. Total contributed: $93,600. Projected balance: $155,352. Tax-free growth: $61,752. This covers about 3 years of a mid-tier public university in 2026 dollars — or roughly 2 years accounting for education inflation.

Scenario 3 — Late start, age 10, $1,200/month: Priya starts late when her daughter is 10. She contributes $1,200/month for 8 years at 6%. Total contributed: $115,200. Projected balance: $140,246. Tax-free growth: $25,046. Starting late requires significantly higher monthly contributions to reach the same target.

529 Plan Savings Projection Table

When to Use This Calculator

• You just had a child and want to know how much to contribute monthly to cover a specific college cost target
• You are comparing your state’s 529 plan returns against a top-rated out-of-state plan to determine whether the state tax deduction is worth staying in-state
• You received a lump sum (inheritance, bonus) and want to model a one-time superfund contribution of up to $90,000 using 5-year gift tax averaging
• You are a grandparent wanting to know how much a one-time $25,000 contribution today grows by the time your grandchild is 18
• You want to determine how much college your current savings will cover after applying 5-6% annual education cost inflation to today’s tuition rates

Common Mistakes to Avoid

1. Starting at age 10 instead of birth. A family contributing $400/month from birth at 7% accumulates $216,654 by age 18. Starting at age 10 with the same $400/month yields only $70,429 — a difference of $146,225 for identical monthly effort. Early starting is the single largest driver of 529 outcomes.

2. Using a too-conservative investment allocation too early. Many families select bond-heavy portfolios “to be safe” when the child is young. A $50,000 balance earning 3% instead of 7% over 10 years reaches $67,196 versus $98,358 — a $31,000 difference. Age-based portfolios that start aggressive (90% stocks) and gradually shift are appropriate until the child is about age 14.

3. Not accounting for education cost inflation. A 4-year private university costs about $240,000 in 2026 at current rates. At 5% annual education inflation, the same degree costs roughly $455,000 in 18 years. Running this calculator with a static today-dollar target will make your savings plan look sufficient when it is not. Always inflate your target cost by 5% annually.

4. Withdrawing for non-qualified expenses. If you take money out for non-education purposes, you owe income tax plus a 10% penalty on the earnings portion. On a $50,000 account where $20,000 is earnings, that penalty is $2,000 plus ordinary income tax on the $20,000 — potentially $6,000-$8,000 in total tax cost.

Current Context for 2026

• Average 4-year public university cost (in-state, 2026): approximately $115,000 total (tuition, fees, room and board)
• Average 4-year private university cost (2026): approximately $240,000 total
• Education cost inflation rate: historically 5-6% annually — roughly double general CPI inflation
• Annual gift tax exclusion: $18,000 per donor per beneficiary; superfunding allows 5x ($90,000) in a single year
• 529-to-Roth IRA rollover (SECURE 2.0): up to $35,000 lifetime per beneficiary; 529 must be open 15+ years; subject to annual Roth IRA contribution limits
• K-12 tuition: up to $10,000/year per beneficiary can be used tax-free from a 529 for private K-12 tuition
• State deduction examples: New York deducts up to $5,000/year (single) or $10,000 (married); Illinois up to $10,000; Colorado offers unlimited deduction

Tips

1. Open the account at birth, even with $25. The earlier the account is open, the longer the compounding period. A single $1,000 contribution at birth grows to roughly $3,380 by age 18 at 7% — that is $2,380 of tax-free growth from one small action.
2. Ask grandparents to skip the toys and contribute to the 529. A $500 birthday contribution from grandparents each year from age 1 to 18 at 7% adds over $17,000 to the college fund. Many plans offer a gift link for direct third-party contributions.
3. Compare out-of-state plans. The Utah my529 and New York’s Direct Plan consistently rank among the lowest-cost 529s in the country. If your state’s plan charges 0.50% in fees and Utah charges 0.08%, the fee gap on a $100,000 balance over 10 years is roughly $4,500.
4. Model education inflation, not just return rate. Run the calculator twice: once with your savings projection and once with your tuition target inflated at 5%/year. The gap between those two numbers is your shortfall.
5. Do not over-fund a single child’s 529. Excess funds face a 10% penalty on earnings for non-qualified withdrawals. Plan conservatively, use a 15-year Roth rollover for truly excess funds, or change the beneficiary to another family member.
6. Front-load contributions in the early years. If you receive a year-end bonus, contribute it to the 529 in January of the new year rather than waiting. Every extra month of compounding in early years compounds forward for 18 years.

Related Calculations

• Compound Interest Calculator — model a one-time lump sum contribution to see exactly how much a single deposit grows over 10-18 years
• Savings Calculator — project regular monthly savings without the education-specific context, useful for comparing 529 versus UTMA/UGMA accounts
• Inflation Calculator — project today’s college cost at 5-6% annual education inflation to set a realistic savings target
• Roth IRA Calculator — model the 529-to-Roth IRA rollover scenario once your child’s education is fully funded
• Investment Return Calculator — compare 529 investment allocation options (aggressive vs. age-based) to understand how allocation affects final balance