Start early and let time do the work. Watch how compounding turns steady contributions into a balance that grows faster and faster the longer you wait.
Compound Interest & InvestingLive
the eighth wonder
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Compounding means earning returns on your past returns, so growth accelerates over time. The gap between the balance line and your total contributions is pure compound interest — and it widens dramatically in the final years. Educational tool, not investment advice.
Reading this result: Rule of 72: at 7.0% a year, money roughly doubles every 10.3 years — about 2 doublings across your 30-year horizon. Each $500/mo contribution then earns returns on its own past returns, so the balance curve pulls away from your flat contribution line. Because compounding is exponential, most of the $501,150 in interest is created in the final years — time in the market matters far more than the amount. Educational tool, not investment advice.
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How it works
Compound interest earns returns on your prior returns, so a balance grows exponentially rather than linearly. This projects a starting amount plus regular contributions at a chosen annual return, and separates how much of the final balance is money you put in versus interest earned. Educational tool, not investment advice.
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The solver uses established numerical methods, but results are for research and educational purposes and should be validated against experiment or professional review before you rely on them.