What the number is
Retirement is not an age, it is a sum of money large enough that it can replace your income for the rest of your life. Working out roughly how large takes ten minutes and almost nobody has done it.
Chapter 1 · Beginner
Retirement is usually described as an age. It is better understood as a balance: the point at which what you own can produce what you need, indefinitely, without you working.
The number
A rough estimate, and rough is enough to change behaviour:
corpus ≈ annual spending in retirement × 25
Multiplying by 25 is the same as assuming you can withdraw 4% of the corpus each year. Chapter 5 examines whether that holds; for now it is a usable first pass.
So a household spending ₹8 lakh a year in retirement needs something like ₹2 crore. Spending ₹15 lakh needs nearer ₹3.75 crore.
Most people's first reaction is that the number is far too large. It is not too large — it is simply the honest size of replacing an income for two or three decades without earning.
Adjusting the spending figure
Your retirement spending is not your current spending, and it moves in both directions.
What stops: commuting, work clothes, children's education once they are independent, your own retirement contributions, the home loan if it is repaid, and the cost of supporting dependants who have become independent.
What continues: housing or rent, food, utilities, travel.
What rises: healthcare, almost without exception, and often by more than general inflation. And more free time frequently means more spending in the early years, not less.
Many people land near 70–80% of pre-retirement spending, and the right way to use that is as a sanity check on your own arithmetic rather than as the arithmetic.
Why the number is bigger than it looks
Three things, and the third is the one nobody includes.
Inflation does not retire. Chapter 7 of Finance 101: ₹8 lakh of spending today is a much larger number in twenty years. The corpus must be sized in future rupees, and it must keep growing during retirement.
Retirement is long. Someone stopping at sixty may need the money for thirty years. That is not a short drawdown; it is a second investing lifetime, which is why the corpus cannot simply sit in cash.
Nothing is assured. PFRDA states it plainly about the NPS, and it generalises to every market-linked vehicle: "there is no implicit or explicit assurance of benefit and the investments are subject to market conditions."
So the corpus is not a guarantee. It is a quantity whose adequacy depends on returns, inflation and how long you live — three things nobody knows in advance. Chapter 6 is how to manage that honestly.
The two levers
Only two things determine whether you arrive.
How much you save, which chapter 3 of Finance 101 established is the gap between income and spending rather than the income itself.
How long it compounds, which chapter 8 of Finance 101 showed is the lever that does the heavy lifting and the one that cannot be recovered later.
Return matters too, and it is the one you control least. Of the three, starting earlier is the only one available for free, and it is available exactly once.
The uncomfortable arithmetic of starting late
Chapter 8 of Finance 101's compounding race, applied here.
Someone saving from twenty-five has forty years of growth on their first contributions. Someone starting at forty has twenty-five. The second person does not need to save a little more — they need to save considerably more, every month, for the rest of their working life, to arrive at the same place.
This is not a reason for despair if you are forty. It is a reason to start today rather than after the next raise, because the same arithmetic applies between today and next year.
What this subject covers
Eight chapters.
Chapters 2 to 4: where retirement money sits in India — the pots you already have, how the NPS actually works, and what an annuity is and is not.
Chapters 5 to 7: the drawdown — how much you can safely take, how to handle the risks of a long retirement, and the transition years that do the most damage.
Chapter 8: the plan, and the end of the Finance stream.
The point
Retirement is a corpus, not an age: roughly twenty-five times what you will spend each year. Adjust current spending for what stops, continues and rises — healthcare always rises. Inflation does not retire and nothing is assured, so the two levers that matter are how much you save and how long it compounds.
Check yourself
4 questions. Every answer is explained afterwards, including the ones you get right — guessing correctly is not the same as knowing. Score 70% or more and the chapter is marked done.
Question 1 of 4
0 of 4 answered. You can submit with questions unanswered — they simply score zero.
Now do it with your own numbers
Take your current annual household spending, subtract what stops at retirement — commuting, children's education, your own savings — and multiply what is left by 25. That is a first estimate of the corpus.
Multiplying by 25 is the same as assuming you withdraw 4% a year. Chapter 5 is whether that assumption holds.