wunder beta📈How does compound interest work
Interest on interest: the multiplicative loop that grows balances and debts over time.
What you’ll learn
- Interest on the InterestDefine compounding as multiplicative growth shaped by rate, frequency, and time.Compound interest applies a rate to an updating base. Frequency and long horizons change outcomes versus simple interest intuition.
- Debt Compounds TooShow the same loop on debt, APR/APY, amortization, and inflation as a separate idea.Balances can grow against you; APR helps compare; amortization schedules allocate interest vs principal; inflation is related but distinct.
- What the Formula Is SayingConnect the (1+r)^n engine, contributions, and model limits without giving advice.The formula is repeated multiplication. Cash flows and real contract rules modify the clean curve, but the feedback mechanism remains.
Questions this course answers
What makes compound interest different from simple interest?
Compounding credits interest to the base so later periods charge or pay on a larger amount; simple interest does not grow the base that way.
Educational check: if a balance grew by a factor of about 1.5 with simple interest over a stretch, a comparable compound path in the bar chart example landed near what relative value?
The lesson chart used an illustrative compound ending near 163 versus 150 simple from 100 — showing multiplicative drift, not a universal law.
In your own words, why does time matter so much under compound interest?
Each period multiplies a growing base, so additional years add more absolute change later than earlier — time is the exponent's friend.
Grounded in trusted sources
- U.S. Securities and Exchange Commission investor education — compounding
- Consumer Financial Protection Bureau — APR and interest explainers
- Federal Reserve education resources on interest concepts
- Open university / textbook treatments of compound interest mathematics
Every Wunder lesson is built from real, reputable sources — never invented.
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