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📈 Compound interestReturns that earn returns — how time turns a rate into an exponential path, and what still breaks the fairy tale.⌛ Time value of moneyA dollar today is not a dollar in ten years — discounting, present value and why waiting has a price.⚖️ Opportunity costEvery choice spends an alternative future — how to price the path you did not take without freezing decisions.
Compound calculatorPrincipal, monthly contributions, expected return, fees and inflation — a growth curve you can read without JavaScript.
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Compound interest
Returns that earn returns — how time turns a rate into an exponential path, and what still breaks the fairy tale.
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⌛Time value of money
A dollar today is not a dollar in ten years — discounting, present value and why waiting has a price.
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⚖️Opportunity cost
Every choice spends an alternative future — how to price the path you did not take without freezing decisions.
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🔢Rule of 72
A mental model for doubling time: divide 72 by the rate — useful, approximate, and easy to abuse.
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🌡️Nominal vs real returns
Headline growth lies when prices rise — how to read returns after inflation eats purchasing power.
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✖️Rule of 115
A cousin of the Rule of 72 for tripling time — still a pocket estimate, still blind to fees and inflation.
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