The honest part
The ride is bumpy
Investments can go up or down. Some years can feel bad. Waiting does not guarantee that a loss comes back.
Grown-up calculator
Explore the assumptions
This tool is intentionally outside the kid lesson. It uses a smooth planning rate, not a market forecast.
Choose your plan
Try a preset or make your own.
Shown in today's buying power. Markets do not grow smoothly.
Rough value at age 65 in today's dollars
$0
from a small head start and a lot of patience
You put in$0
Growth did$0
Growth share0%
3.5% plan$0/mo
Watch the curve
Slow first. Powerful later.
InvestedCash savedDeposits stop
The time comparison
Start now or wait ten years?
Same monthly amount. Both keep adding until the goal age. The only difference is when they begin.
Plan possible earnings
Turn neighborhood jobs into a simple plan
Try a weekly plan with a grown-up's permission. This estimates gross earnings before expenses and taxes. Paid work is one way money can arrive; it never measures a person's worth.
Dog walks$15 each · times per week
$0/mo
Car washes$20 each · times per month
$0/mo
Lawn jobs$30 each · times per month
$0/mo
A real plan can be smaller. Two steady customers are more useful than ten ideas that never happen.
Grown-up guide
Details without the clutter
The calculators, comparison tables, account options, tax notes, and sources are organized here for adult review.
Open a tool when you need it; its close button stays visible while you scroll.
Assumptions and what the numbers mean
The kid example uses a constant 5% annual return after inflation so its result is expressed in today's buying power. The grown-up calculator lets that real-return assumption change. Projections use end-of-month contributions and convert the selected effective annual return to its mathematically equivalent monthly rate. They still exclude taxes, investment expenses, and market volatility. Actual returns arrive unevenly and can be negative for long periods.
Retirement income is an illustration. The displayed 3.5% amount is simply 3.5% of the projected balance divided by 12. A withdrawal rule is not guaranteed income, does not eliminate sequence-of-returns risk, and does not promise that principal will remain untouched. The older 4% rule was built around a roughly 30-year horizon; longer retirements may call for more conservative and flexible planning.
Why the math changed: the former calculator divided the annual rate by 12, making an 8% selection compound to about 8.30% per year. This version uses (1 + annual rate)^(1/12) - 1, so the selected annual rate and the calculation now agree.
Saving-versus-investing comparison lab
These tables compare $100, $300, and $400 monthly contributions using hypothetical 3% and 5% annual growth after inflation. They use end-of-month contributions and show today's buying power before fees and taxes.
| Monthly / years | Contributed | At 3% | At 5% |
|---|
Front-load it, then stop
Invest $500/month for 20 years, then make no deposits for another 30 years:
| Return | At year 20 | At year 50 | Total contributed |
|---|
A relatable time example
At the same smooth 5% after-inflation assumption, a one-time $1,000 could become about after 10 years, after 30 years, or after 50 years. These are hypothetical—not targets or promises. The lesson is simply that more time gives possible growth more chances to build on itself.
Retirement-income showcase
This hypothetical $400/month example starts at age 11. The balance and 3.5%/4% illustrations are shown together.
| Goal age | Balance at 3% | 3.5% / 4% income | Balance at 5% | 3.5% / 4% income |
|---|
Brokerage plus a fully funded Roth illustration
This two-account example uses $400/month in a taxable brokerage plus $625/month—the 2026 $7,500 IRA limit divided by 12—and assumes sufficient eligible compensation every year. It does not model tax drag in the brokerage.
| Goal age | Total at 3% | 3.5% / 4% income | Total at 5% | 3.5% / 4% income |
|---|
Roth IRA path, records, and tax checkpoint
Example custodial Roth IRA path
- Document real earned income from work.
- Confirm eligible compensation and the allowed contribution for that tax year.
- Compare reputable custodians, including their fees, features, and transfer process.
- Choose investments only after reviewing their objectives, diversification, risks, and costs.
- Review the account, records, and current rules once a year.
Simple record
| Date | Work | Customer | Paid | Expense |
|---|---|---|---|---|
| Sample date | Dog walk | Customer A | $15 | $0 |
| Sample date | Car wash | Customer B | $20 | $3 supplies |
Keep receipts for soap, sponges, bags, treats, printing, gas, replacement parts, and other ordinary business expenses. Gross payments minus eligible expenses produce net profit; IRA compensation and tax calculations can require further adjustments.
Tax reminder: the standard deduction can eliminate federal income tax, but it does not automatically eliminate filing or self-employment tax. Net self-employment earnings of $400 or more generally require Form 1040 and Schedule SE, regardless of age. Confirm the actual treatment each year.
For 2026, the IRA contribution limit is $7,500. A Roth contribution is also limited by eligible compensation and other Roth rules. Contributions for a tax year are generally due by that year's return due date, not including extensions.
Account choices compared
| Account | Earned income? | Tax treatment | Access/control | Best fit |
|---|---|---|---|---|
| Custodial Roth IRA | Yes | Qualified retirement withdrawals can be tax-free | Custodian now; ownership-transfer process later | Very long-term retirement |
| UTMA/UGMA | No | Taxable investment account; kiddie-tax rules may apply | Irrevocable gift to the child; state transfer age applies | Flexible child-owned investing |
| 529 | No | Tax advantages for qualified education use | Account owner controls use | Education |
| Adult's brokerage | No | Taxable to the adult owner | Adult owns and controls it | Maximum adult flexibility |
Custodial account providers have their own transfer processes when a child becomes an adult, and state rules can affect the timing. Verify the current provider process rather than assuming an automatic same-account conversion.
Sources, teaching inspiration, and as-of date
Rules checked August 22, 2026. Recheck them before making each year's contribution.
- SEC Investor.gov: Stocks — ownership, potential growth, and loss risk.
- SEC Investor.gov: What is risk? — investments can lose value and are not deposit-insured.
- IRS retirement-plan limits — 2026 IRA limit: $7,500.
- IRS Publication 590-A — compensation, Roth eligibility, limits, and contribution timing.
- IRS self-employment tax guidance — $400 net-earnings trigger and Schedule SE.
Teaching inspiration
The kid activities use short, age-appropriate practice; connect money to real goals; teach saving before long-term investing; and emphasize patience, flexibility, comparison awareness, and room for error.
- KidVestors — game-based, age-appropriate financial learning.
- Eastspring: explaining investments to children — build from saving and real-life examples.
- Schwab MoneyWise: introduction to investing — simple goals, time, risk, and inflation.
- U.S. Bank: investing for kids — goal-setting, patience, and regular habits.
- Morgan Housel: The Psychology of Money — behavior, patience, freedom, and avoiding comparison.
This dashboard provides general financial education, not individualized investment or tax advice.