Retirement planning has a reputation for being overwhelming — endless spreadsheets, dozens of assumptions, conflicting advice. In reality, it comes down to answering one question clearly: how large does your portfolio need to be so that it can fund your lifestyle indefinitely, without you ever running out?
The 25x rule (also called the 4% rule)
The most widely used framework in retirement planning: multiply your annual expenses by 25. A portfolio of that size, invested moderately conservatively at 7-8% returns, can fund your lifestyle indefinitely — you withdraw about 4% of the corpus per year, while the rest keeps growing to offset inflation and future withdrawals.
What that means in real numbers
| Monthly Expenses at Retirement | Annual Expenses | Retirement Corpus Needed |
|---|---|---|
| ₹30,000 | ₹3.6 Lakhs | ₹90 Lakhs |
| ₹50,000 | ₹6 Lakhs | ₹1.5 Crore |
| ₹75,000 | ₹9 Lakhs | ₹2.25 Crore |
| ₹1,00,000 | ₹12 Lakhs | ₹3 Crore |
Why you can't use today's expenses directly
Your expenses in retirement will be considerably higher than today's numbers, purely due to inflation. At 6% average inflation, a ₹50,000/month lifestyle today requires roughly ₹90,000/month in just 10 years to maintain the same standard of living. If you're planning to retire 20-30 years from now, this effect compounds significantly — always project your expenses forward to your retirement year, not backward from today.
A worked example
Suppose you're 30 today, plan to retire at 60, and currently spend ₹50,000/month. At 6% inflation over 30 years, that lifestyle will cost roughly ₹2,87,000/month by the time you retire — pushing your required corpus (using the 25x rule on the inflated annual figure) to well above ₹8 crore, not the ₹1.5 crore the un-inflated number would suggest. This is exactly why retirement planning done on today's expense numbers systematically undershoots the real target.
When should you recalculate your number?
Revisit your retirement corpus target every few years, and especially after any major lifestyle change (having children, relocating to a different city, a significant health event) — these shift your baseline expenses enough to meaningfully move your target.
Common mistakes to avoid
- Using today's expenses without adjusting for inflation over a 20-30 year runway.
- Assuming a single withdrawal rate forever — 4% is a reasonable starting point, but healthcare costs typically rise faster than general inflation as you age.
- Underestimating how long retirement lasts — with rising life expectancy, planning for 25-30+ years post-retirement is increasingly realistic.
- Not separating essential expenses from lifestyle expenses — knowing the difference helps you flex spending in a market downturn without real hardship.
Key takeaways
- Multiply your inflation-adjusted annual expenses at retirement by 25 to get your target corpus.
- A 6% inflation assumption roughly doubles expenses (and thus your target corpus) every 12 years.
- Recalculate periodically — retirement planning isn't a one-time exercise.
- Use the Retirement Calculator to project your own inflation-adjusted number.
FAQs
Is the 25x rule the same as the FIRE number?
Yes, it's the same underlying formula used by the FIRE movement — see FIRE movement explained for Indian salaried employees for how it applies to early retirement specifically.
Can I retire before the traditional age of 58-60?
Yes, with a higher savings rate and enough runway — see can you retire before 50 in India for the specific math.
Should my retirement corpus be entirely in equity?
Typically no — as retirement nears, a gradual shift toward a more conservative mix (part equity, part debt) reduces the risk of a market downturn hitting right when you start withdrawing.