Level 2 · Module 1 · Foundations
Compounding: The Eighth Wonder
Boring for 10 years, then suddenly astonishing.
In this lesson
What you'll be able to do
- Explain compounding without formulas
- Use the Rule of 72
- See why starting early beats investing more
Think about it
Two people invest the same total amount. One starts at 22 and stops at 32. The other starts at 32 and never stops. Who ends with more at 60?
Story
Let's picture it
Usually the one who started at 22, and quit. Ten years of early contributions get 38 extra years of growth on top. The late starter contributes almost three times as much money and still struggles to catch up. Compounding rewards time far more than it rewards effort.
Visual
₹5,000/month at 12% (illustrative)
- 1
Year 5
Invested ₹3.0L → ≈ ₹4.1L
- 2
Year 10
Invested ₹6.0L → ≈ ₹11.6L
- 3
Year 20
Invested ₹12.0L → ≈ ₹50L
- 4
Year 30
Invested ₹18.0L → ≈ ₹1.76cr
Plain English
The simple explanation
Compounding is earning returns on your returns. The first years feel pointless; the last years do the heavy lifting.
Rule of 72: divide 72 by the annual return to estimate doubling time. At 12%, money doubles roughly every six years.
The three inputs are amount, rate and time. You control amount and time reliably; nobody controls the rate.
Real world
EPF
Salaried Indians compound quietly through EPF for decades without watching it. Many are surprised at the final corpus precisely because they never interrupted it, the interruption is what usually breaks compounding.
Watch out
Common mistakes
- Withdrawing early and restarting
- Chasing a higher rate instead of adding years
- Assuming a fixed 12%, real returns vary every single year
Did you know?
The numbers above are illustrations of a formula, not a forecast. Real equity returns arrive unevenly, some years negative.
Your turn
Mini challenge
Open the SIP calculator on this site. Compare starting today vs starting in five years, same amount. Note the gap.
Quick quiz
1 / 3
Wrap up
Summary
Compounding turns time into money. Start early, don't interrupt, and let the last decade do the work.
- Returns on returns
- 72 ÷ rate = doubling years
- Time beats amount
Revise