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Built for Gen Z & Millennials

Start at 20.
Not 30.

That's $356,000 more by retirement.

Start at 20
$736,000
VS
Start at 30
$380,000
Calculate my money
$226,049
Your projected wealth

"With 100K+ invested in the stock market, you're basically guaranteed to never stress about money again. And it's way simpler than you think."

Free Compound Interest Simulator

Move the sliders. Watch your future change in real-time.

$500
$0$10M
$100
$0$50K
10%
1%100%
Historical annual returns (for reference)
S&P 500 ~10.5% 1957-2024
NASDAQ ~12.2% 1985-2024
MSCI World ~8.5% 1987-2024
Bonds ~4.5% Avg. US Treasury
Savings Acct ~2% Avg. high-yield
Inflation ~3.2% US avg. 1960-2024

Default 10% = S&P 500 average. Conservative but realistic long-term.

30 years
1 yr100 yrs
Unlock inflation projections, S&P 500 benchmark, PDF export & more
Double-click to expand
$0
You put in
$0
Market gave you
0x
Money multiplied
-
To hit $100K

* Illustrative projections only — not financial advice. Assumes constant annual return. Actual results will vary.

Your milestones

Each one brings you closer to financial freedom.

Starting at 20 vs 30

Same monthly amount. 10 years difference. Life-changing gap.

You (starting now)
Start at 20
$0
by age 50
VS
Start at 30
$0
by age 50

They all started young

The world's greatest investors didn't wait. Neither should you.

Warren Buffett

CEO, Berkshire Hathaway
Bought his first stock at age 11
"Someone's sitting in the shade today because someone planted a tree a long time ago."

Mark Zuckerberg

CEO, Meta
Built Facebook at age 19
"The biggest risk is not taking any risk."

Jeff Bezos

Founder, Amazon
Started Amazon at age 30
"I knew that if I failed I wouldn't regret that. I knew the one thing I might regret is not trying."

Elon Musk

CEO, Tesla & SpaceX
Sold first code at age 12
"When something is important enough, you do it even if the odds are not in your favor."

Ray Dalio

Founder, Bridgewater Associates
Bought first stock at age 12
"He who lives by the crystal ball will eat shattered glass."

Peter Lynch

Former Manager, Fidelity
Averaged 29% returns per year
"Know what you own, and know why you own it."
92%
of millionaires built wealth through consistent investing, not inheritance
$1.2M
what $200/month becomes in 40 years at market average returns
8.5x
more wealth for someone who starts at 20 vs 35, with the same monthly amount

Ready to start for real?

The simulator showed you the math. Now here are platforms where you can actually begin investing, even with small amounts.

* Some links below are affiliate links — we may earn a small commission at no cost to you.

These are suggestions, not financial advice. Always do your own research before choosing a broker.

Free vs Pro

Start free. Upgrade when you're ready to unlock the full ecosystem.

Free

$0 forever
Investment simulator
Compound interest chart
Milestones tracker
Age comparison (20 vs 30)
Share your results
Multi-language support
Save 1 simulation (local)
Historical returns reference
🔒 Dividend Calculator
🔒 Tax Wizard
🔒 Net Worth Tracker
🔒 Dream Fund
🔒 Cloud sync + unlimited saves
🔒 Export PDF reports
Start for free
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Pro

$4.99 /month
Everything in Free
Dividend Calculator PRO
Tax Wizard PRO
Net Worth Tracker PRO
Dream Fund PRO
S&P 500 / NASDAQ / MSCI comparison PRO
Cloud sync across all devices
Unlimited simulations saved
Export reports as PDF
Priority support

14-day free trial. Cancel anytime before it ends — you won't be charged.

About this compound interest calculator

What is a compound interest calculator?

A compound interest calculator shows how your money grows exponentially when returns are reinvested. This free simulator calculates investment growth year-by-year, factoring in your starting amount, monthly contributions, annual return rate, and time horizon.

How much does starting at 20 vs 30 matter?

Investing $200/month at a 10% annual return starting at age 20 gives you roughly $736,000 by age 55 — versus $380,000 starting at 30. That's a $356,000 gap from just 10 years of delay. Compound interest rewards early starters more than any other factor.

Is this investment simulator free?

Yes — the compound interest simulator is 100% free and requires no account. You can see instant results in seconds. No email, no credit card. Pro features (PDF export, advanced scenarios) are optional.

What return rate should I use?

The S&P 500 has averaged around 10% annually over the past century (7% after inflation). For a conservative estimate, use 6–7%. For index funds or ETFs, 8–10% is a common benchmark for long-term projections.