There's no single number that works for everyone — anyone who gives you one flat figure ("₹5 crore!") is skipping the part that actually matters: your number depends entirely on your own expenses, your timeline, and how you account for inflation over decades. Here's the actual framework, not a guess.
Start from today's expenses, not a guess about the future
The most reliable starting point is your current monthly spending — not your income, your spending. If you spend ₹40,000/month today, that's your real baseline. Trying to estimate future expenses directly, without anchoring to a real current number, tends to produce wildly unreliable guesses.
Inflation is the part almost everyone underestimates
This is the single biggest reason retirement number calculations go wrong. At even a modest 6% average inflation, prices roughly double every 12 years. If you're 30 now and plan to retire at 60, that's 30 years away — at 6% inflation, today's ₹40,000/month becomes roughly ₹2,30,000/month by the time you retire, just to maintain the same standard of living. People who plan around today's expense number without adjusting for this dramatically underestimate what they'll actually need.
Your corpus needs to last decades, not just get you to retirement
The other common mistake is only planning for the savings phase and not the spending phase. If you retire at 60 and live to 85, your money needs to last 25 years — during which inflation keeps running, so your expenses keep rising even after you've stopped earning. A common approach here is a "safe withdrawal rate" — commonly cited around 4% per year — where you calculate how large a corpus needs to be so that withdrawing that percentage annually reasonably covers your rising expenses without running out.
A simplified worked example
Someone aged 30, planning to retire at 60, spending ₹40,000/month today, assuming 6% inflation and a 4% safe withdrawal rate:
- Monthly expense at retirement (inflation-adjusted): roughly ₹2,30,000
- Annual expense at retirement: roughly ₹27.6 lakh
- Required corpus (annual expense ÷ 4%): roughly ₹6.9 crore
That number often surprises people the first time they see it — which is exactly why "just save a fixed amount and hope" tends to fall short. Working backward from that corpus to a required monthly SIP (assuming a reasonable pre-retirement investment return) is what turns an intimidating lump sum into an actionable monthly target.
What this framework doesn't account for
- Major one-time costs — a child's education or wedding, medical events — need to be planned separately from routine monthly expenses.
- Your expenses may not stay flat — some categories (healthcare) often rise faster than general inflation as you age; others (a paid-off home, no commuting costs) may fall.
- Existing savings and pensions reduce how much new saving you need — this framework calculates the total corpus required, not what's left to save if you already have EPF, existing investments, or a pension coming.
The real takeaway
The point of working out an actual number isn't to get a perfectly precise figure — it's to replace vague anxiety ("I should probably save more") with something concrete enough to act on. Even a rough, honestly-calculated number is far more useful than no number at all, and it's worth recalculating every few years as your expenses and assumptions change.
Work out your own retirement corpus and the monthly SIP needed to reach it.
Try the Retirement Calculator →This is general information, not personalized financial advice. Actual inflation, investment returns, and life expectancy are uncertain and will differ from any single assumption used here — consult a financial advisor for planning specific to your situation.