College Fund Calculator

A college savings fund grows through a combination of regular contributions and compound interest over many years. The most common vehicle in the United States is the 529 plan, which offers tax-free growth and tax-free withdrawals for qualified education expenses.

Future Value of Regular Contributions formula (annuity): FV = PMT × [((1 + r)ⁿ − 1) / r]

What each variable means:

• FV — future value of the fund at the target date (e.g., when the child turns 18)
• PMT — monthly or annual contribution amount
• r — periodic interest rate (annual rate ÷ 12 for monthly contributions)
• n — total number of contribution periods

Worked example: A parent opens a 529 plan when their child is born and contributes $300/month for 18 years. The fund earns 7% annually (average stock-market-linked return).

r = 7% / 12 = 0.5833% per month n = 18 × 12 = 216 months FV = $300 × [((1.005833)²¹⁶ − 1) / 0.005833] FV = $300 × [(3.4607 − 1) / 0.005833] FV = $300 × [2.4607 / 0.005833] FV = $300 × 421.9 = $126,570

Total contributed: $300 × 216 = $64,800. Investment growth: $126,570 − $64,800 = $61,770 — nearly doubling the contributions.

Reference costs (2024–2025):

• Public in-state university: ~$11,000/year tuition + fees
• Public out-of-state: ~$29,000/year
• Private 4-year college: ~$43,000/year
• 4-year total (tuition only): $44,000–$172,000+

529 plan benefits:

• Contributions grow tax-free federally
• Withdrawals for education are tax-free
• Over 30 states offer a state income tax deduction on contributions
• Unused funds can be rolled over to a Roth IRA (up to $35,000 lifetime limit, as of 2024)

Tip: Starting at birth versus age 5 can nearly double the fund at age 18, thanks to compounding. Even small early contributions have a large long-term impact.