What is compound interest?

Compound interest is interest earned on both your original investment and the interest it has already earned. Unlike simple interest, compounding means your money grows faster over time because each year's gains become part of the base that earns the next year's gains. A $200/month investment at 9% average annual return grows to roughly $580,000 over 30 years even though you only contributed $72,000.

How much does $200 a month grow over 30 years?

At 9% average annual return (VTI historical), $200 per month invested consistently over 30 years grows to approximately $580,000. You contributed $72,000 of your own money. The remaining $508,000 came from compound growth, meaning the market did more than 87% of the work for you.

Is it better to start investing small amounts early or wait until you can invest more?

Start small and start now. Time in the market beats the amount invested. A warehouse worker who invests $100/month starting at age 25 will have more at retirement than someone who waits until 35 and invests $200/month, even though the second person put in more total dollars. The early years compound into the later years. Every year you wait shrinks your final number more than you expect.

Compound Interest Calculator | See What $200/Month Becomes

Educational tool only: Projections assume a consistent annual return and monthly compounding. Actual investment returns vary. This is not financial advice.

Run the Numbers

Monthly Contribution: $200

Starting Amount (optional): $0

Annual Return Rate: 9%

Years to Grow: 30

yrs

Total Balance at End

$298,072

"That's the machine working for you. Not you working for it."

You Contributed

$72,000

Your actual dollars in

Growth Split

76%

of your balance is market growth

Your money made this for you

$226,072

That's the compound interest your contributions earned, without you lifting a finger.

Balance Growth Over Time

Results assume the stated annual return compounded monthly. Past market performance does not guarantee future results. Index fund averages have historically ranged from 7% to 10% annually over long periods, but individual results vary. Consult a financial professional for personalized advice.

$226,072

How much the market contributes on top of $200/month over 30 years at 9% (the W2W standard). You put in $72,000. Compounding added the rest.

What Compound Interest Actually Is

Compound interest is interest earned on interest. You invest $200 this month. It earns a return. Next month, that return also earns a return. The month after that, the return-on-the-return earns a return. It sounds small at first. Over 30 years, it becomes the dominant force in your portfolio.

The simple version: your money makes money, and then that money makes more money. It keeps going until you pull it out or the clock runs out.

Why Starting Early Beats Investing More Later

Time is the key variable. Not the amount. A warehouse worker who starts at 25 with $100 per month will have more at 60 than someone who starts at 35 with $200 per month, even though the second person invested more total dollars. The first 10 years of compounding are doing work that the second person can never buy back.

Run the numbers: $100/month from age 25 to 60 (35 years at 9%) = roughly $229,000. $200/month from age 35 to 60 (25 years at 9%) = roughly $195,000. The person who invested half as much but started earlier wins by $34,000. Time matters more than amount.

The Warehouse Worker Example

The median logistics worker earns around $45,000 per year. That's roughly $3,750 per month before taxes. Five percent of that, $187.50, rounds up to $200. A contribution barely noticeable in a monthly budget, especially if it's going directly into a 401k before the paycheck hits your bank account.

Over a 30-year logistics career, at 9% average annual return (VTI historical nominal return), that $200/month builds to approximately $298,000. If your employer also matches even 50 cents on the dollar up to a threshold, the number climbs past $400,000. The people who end up with nothing at retirement weren't bad earners. They just never started the machine.

The W2W Connection

This is Step 8 of the Logistics to Legacy framework: Invest Simply. You don't need complex strategies. You don't need a financial advisor charging 1% per year. You need a 401k, index funds, and 20 or 30 years. The compound interest calculator above shows you the end state. The framework shows you how to get there from wherever you are right now.

If your employer offers a match and you're not capturing all of it, that's the first thing to fix. Start with the 401k Match Calculator to see how much free money you're currently leaving on the table. Then come back here and run the numbers with that match included.

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