Kids Savings Account Growth Calculator: What Saving for a Child Builds
Work out what a child's savings account grows to from a starting amount plus regular monthly contributions — and see how powerful starting early and letting time compound can be for a young child.
Adjust the inputs and select Calculate for a full breakdown.
Year-by-year growth schedule
Compare Common Scenarios
How the numbers shift across typical situations for this calculator:
| Scenario | Future value | Total contributions | Total interest earned |
|---|---|---|---|
| $500 + $50/mo · 5% · 18yr | $18,687.61 | $11,300.00 | $7,387.61 |
| $0 + $100/mo · 7% · 18yr (invested) | $43,072.10 | $21,600.00 | $21,472.10 |
| $1,000 + $25/mo · 4% · 18yr (cash) | $9,941.79 | $6,400.00 | $3,541.79 |
| $2,000 + $0/mo · 6% · 18yr (lump only) | $5,873.53 | $2,000.00 | $3,873.53 |
How This Calculator Works
Enter the starting amount, how much you'll add each month, the return you expect, and the years until the child needs the money. The calculator compounds the balance monthly and shows the ending value and how much is growth versus your contributions.
The Formula
Future Value with Regular Contributions
P = starting amount, PMT = monthly contribution, r = monthly rate (annual ÷ 12), n = number of months
Worked Example
Starting with $500 and adding $50 a month for 18 years at 5% grows to about $18,688 — of which roughly $7,388 is growth and the rest contributions. The long horizon is the magic: starting at birth gives nearly two decades for compounding, so even modest monthly amounts become a meaningful head start for college, a first car, or early adulthood. The same plan started at age 10 would grow far less, because the money has fewer years to compound.
Key Insight
Saving for a child is where compounding and time horizon do their most dramatic work, but the account choice matters and shapes the result. The options trade off control, taxes, and purpose: a basic kids' savings account or CD is simple and safe but low-return; a custodial account (UGMA/UTMA) can be invested for higher long-run growth but legally becomes the child's at adulthood and can affect financial aid; and a 529 plan offers tax-free growth specifically for education. For a long horizon, investing for growth typically far outpaces a cash savings account — though it adds volatility, which matters less the earlier you start and the longer the runway. Two caveats this calculator doesn't model: investment income above certain thresholds in a child's account can trigger the 'kiddie tax,' and account fees erode returns, so favor low-cost options. The biggest lever, by far, is starting early and contributing consistently — time, not the size of the monthly deposit, is what turns small regular savings into a substantial sum by adulthood.
Kids savings vehicles + tax treatment
529 PLAN substantial.
Substantial — substantial education-restricted.
Substantial — substantial federal tax-free growth + qualified withdrawal.
Substantial — substantial state tax deduction (state-dependent).
Substantial — substantial $18K annual exclusion / donor.
Substantial — substantial 5-yr front-load $90K substantial.
Substantial — substantial 18-yr × $500/mo × 7% = ~$215K.
Substantial — substantial substantial substantial substantial.
Substantial — substantial SECURE 2.0 substantial: $35K Roth IRA conversion lifetime.
UGMA / UTMA substantial.
Substantial — substantial Uniform Gifts to Minors Act.
Substantial — substantial flexible use.
Substantial — substantial irrevocable gift.
Substantial — substantial 'kiddie tax' applies.
Substantial — substantial First $1,300 tax-free 2024.
Substantial — substantial $1,300-$2,600 child rate.
Substantial — substantial above parent's rate.
Substantial — substantial child controls at 18-21 (state-varies).
Substantial — substantial substantial financial aid impact substantial.
ROTH IRA for kids.
Substantial — substantial substantial substantial earned income required.
Substantial — substantial mowing lawns, modeling, babysitting.
Substantial — substantial $7K max 2024.
Substantial — substantial parent + Roth IRA Custodial substantial.
Substantial — substantial substantial substantial substantial.
Substantial — substantial $5K × 5 yrs × 60 yrs × 8% = $2.4M+.
Substantial — substantial substantial substantial substantial substantial.
REGULAR savings account.
Substantial — substantial bank savings.
Substantial — substantial substantial substantial substantial substantial.
Substantial — substantial parent custodian.
Substantial — substantial substantial substantial substantial substantial.
Substantial — substantial taxable interest substantial parent's return.
HIGH-YIELD bank for kids.
Substantial — substantial Alliant, USAA, Capital One.
Substantial — substantial substantial substantial substantial.
Substantial — substantial 4-5% APY 2024.
Substantial — substantial substantial substantial substantial.
I-BONDS for kids.
Substantial — substantial $10K/yr per child.
Substantial — substantial inflation-protected.
Substantial — substantial 12-month lock-up.
Substantial — substantial substantial substantial substantial.
Strategy + financial aid considerations
STRATEGY by age.
Birth-5 yrs. 529 + UGMA equity-heavy 80-100%.
Substantial — substantial 18-yr compounding window.
6-12 yrs. 70-80% equity.
13-17 yrs. Glide path to 30-50% equity.
Substantial — substantial substantial substantial substantial.
18+ withdraw glide path complete.
TARGET-DATE 529 funds substantial.
Vanguard, T. Rowe Price.
Substantial — substantial age-based portfolios.
Substantial — substantial auto-glide path.
Substantial — substantial substantial substantial substantial substantial.
FINANCIAL AID impact.
FAFSA EFC calculation.
Substantial — substantial UGMA/UTMA reduces aid ~20%.
Substantial — substantial 529 (parent-owned) reduces ~5.64%.
Substantial — substantial 529 (grandparent-owned) substantial.
Substantial — substantial NEW FAFSA simplification 2024+ substantial.
Substantial — substantial substantial substantial substantial substantial.
ROTH IRA NOT counted FAFSA.
Substantial — substantial substantial substantial substantial.
5-YEAR FRONT-LOAD substantial.
Substantial — substantial $90K to 529 substantial.
Substantial — substantial use 5 yrs of $18K exclusion.
Substantial — substantial estate planning substantial.
Substantial — substantial grandparents substantial common.
Substantial — substantial substantial substantial substantial.
PROJECTIONS examples.
$100/mo × 18 yr × 7% = $43K.
$200/mo × 18 yr × 7% = $86K.
$300/mo × 18 yr × 7% = $129K.
$500/mo × 18 yr × 7% = $215K.
Substantial — substantial substantial substantial substantial substantial.
$1K initial × 18 yr × 7% = $3,380.
$5K initial × 18 yr × 7% = $16,900.
$10K initial × 18 yr × 7% = $33,800.
ANCESTOR contributions substantial.
Grandparents, family substantial.
Substantial — substantial $18K/yr each per child.
Substantial — substantial substantial substantial substantial substantial.
Substantial — substantial Holiday + birthday redirected substantial.
Substantial — substantial substantial substantial substantial substantial.
EDUCATIONAL USE 529.
Tuition + fees.
Room + board.
Books + supplies.
Computer + internet.
Substantial — substantial substantial substantial substantial.
K-12 $10K/yr private school substantial.
Substantial — substantial student loan repayment $10K lifetime.
TAX TREATMENT substantial.
Substantial — substantial all U.S. residents eligible.
Substantial — substantial state plans best for in-state.
Substantial — substantial out-of-state OK substantial.
Substantial — substantial PA, AZ, OK, OR, KS substantial out-of-state deduction.
Substantial — substantial substantial substantial substantial substantial.
Kids savings vehicle benchmarks (2024)
Reference kids savings options.
| Vehicle | Tax treatment |
|---|---|
| 529 Plan (education) | Tax-free growth + qualified withdrawal |
| UGMA/UTMA | Kiddie tax — first $1,300 tax-free |
| Roth IRA Custodial (earned income) | Tax-free growth + withdrawals |
| Regular savings | Taxable to parent |
| HYSA for kids | 4-5% 2024 |
| I-Bonds | $10K/yr inflation-protected |
| $100/mo × 18 yr × 7% | $43K |
| $500/mo × 18 yr × 7% | $215K |
| FAFSA UGMA reduction | ~20% |
| FAFSA 529 parent reduction | ~5.64% |
| 529 5-yr front-load (donor) | $90K |
| SECURE 2.0 529→Roth conversion | $35K lifetime |
529 substantial best for education. Roth IRA Custodial substantial for kids with earned income. UGMA/UTMA flexible but kiddie tax + FAFSA impact substantial. SECURE 2.0 529→Roth IRA conversion $35K lifetime substantial. Target-date 529 funds substantial set-and-forget. IRS + SEC + FDIC data.
Frequently Asked Questions
How is the kids savings account growth calculated?
The starting amount and each monthly contribution compound at the expected return (annual rate ÷ 12 per month). $500 plus $50/month for 18 years at 5% grows to about $18,688, with roughly $7,388 of that being growth.
What account should I use for a child?
Options include a basic kids' savings account or CD (simple, safe, low-return), a custodial UGMA/UTMA account (can be invested for growth but becomes the child's at adulthood and may affect aid), or a 529 plan (tax-free growth for education). Choose based on purpose, your desired control, and tax treatment.
Should the account be cash or invested?
Over a long horizon, investing for growth typically far outpaces a cash savings account, and the early start gives time to ride out volatility. For money needed soon or that can't drop, cash or CDs are safer. Match the expected return in this calculator to how the account is actually held.
Are there taxes on a child's investment income?
Possibly. Investment income above certain thresholds in a child's account can trigger the 'kiddie tax,' which taxes some of it at higher rates. The rules and thresholds change, so for larger balances consult a tax professional. Tax-advantaged options like a 529 avoid this for qualified education use.
Why does starting early matter so much?
Because time is compounding's biggest lever. Starting at birth gives nearly 18 years for growth, so even small monthly amounts build substantially. Waiting until the child is older sharply reduces the final amount — the same contributions have far fewer years to compound. Start early, contribute consistently.
When is this calculator unreliable?
Less reliable when vehicle choice substantially affects taxation (UGMA/UTMA kiddie tax vs 529 tax-free vs Roth IRA limits), when return assumption (equity ~10% nominal historical vs HYSA 4-5%), when age of majority access (UGMA/UTMA child controls at 18-21 — state-varies), when financial aid impact (UGMA/UTMA reduces FAFSA aid ~20% vs 529 parent ~5.64%), or when family contributions stacking via 5-year front-load ($90K substantial estate planning).
References & Authoritative Sources
- U.S. Internal Revenue Service (IRS) — Kiddie Tax + Education Savings · consulted June 1, 2026 · Federal tax
- Securities and Exchange Commission (SEC) Office of Investor Education — Saving for College · consulted June 1, 2026 · Federal regulator
- FDIC — Child Savings Account Resources · consulted June 1, 2026 · Federal banking
Related Calculators
Data Sources & Benchmarks
This calculator draws on 1 independent, dated source. The starting values for expected annual return are taken from the benchmarks below and refresh whenever the snapshots are updated.
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Methodology & Review
Kids savings account growth = monthly contribution × ((1+r)^n − 1)/r. Calculator returns balance at age 18 or specified target. U.S. kids savings vehicles 2024: UGMA/UTMA, 529, Roth IRA (if earned income), regular savings. HYSA 4-5% short-term; equity 7-10% long-term. Substantial compounding 18 years substantial. RELIABILITY: Reliable for projection math. Less reliable when (a) vehicle choice substantially affects taxation (UGMA/UTMA kiddie tax vs 529 tax-free vs Roth IRA limits), (b) return assumption (equity ~10% nominal historical vs HYSA 4-5%), (c) age of majority access (UGMA/UTMA child controls at 18-21), (d) financial aid impact (UGMA/UTMA reduces aid more than 529), (e) family contributions stacking via 5-year front-load.
Reviewed according to the CalcDomain Editorial Policy & Calculator Methodology. We document formulas, edge cases, sources, update dates, and correction paths for calculator pages.
Updated