"How much do I need to retire?" is the single most common question we get asked — and it almost never has a one-size-fits-all answer. But it does have a structured, calculable answer specific to you. Here's how we actually work it out.
Step 1: Know Your Real Monthly Expense
Start with what you actually spend today, not a rough guess. Include:
- Household and living expenses
- Healthcare and insurance premiums
- Travel and lifestyle spending
- Any support you provide to family
Most people underestimate this by 20-30% because they forget irregular annual expenses (festivals, maintenance, medical emergencies).
Step 2: Adjust for Inflation to Your Retirement Date
Your expenses won't stay the same — they'll grow with inflation every year until you retire. If you're 40 now, plan to retire at 60, and spend ₹60,000/month today, at 6% inflation your expense at retirement will be:
₹60,000 × (1.06)^20 ≈ ₹1,92,000/month
This step alone is why so many retirement plans fall short — people plan for today's cost of living, not the cost of living 20 years from now.
Step 3: Estimate Your Retirement Duration
With rising life expectancy, planning for 25-30 years in retirement is now realistic for someone retiring at 60. Underestimating this is one of the most common and costly retirement planning mistakes.
Step 4: Calculate the Required Corpus
Using your future monthly expense, retirement duration, and an assumed post-retirement return (net of inflation), you can calculate the corpus required to sustain that expense — growing with inflation — for your entire retirement.
This isn't a simple multiplication. It uses a present-value-of-a-growing-annuity calculation that accounts for the fact that your corpus keeps earning a return even as you withdraw from it.
Rather than working this out by hand, use our Retirement Corpus Calculator — enter your current age, retirement age, life expectancy, monthly expense, and return assumptions, and it computes the number instantly, along with the monthly SIP needed to build it.
A Worked Example
For someone who is 35 today, plans to retire at 60, expects to live to 85, spends ₹60,000/month today, and assumes 6% inflation, 12% pre-retirement returns, and 8% post-retirement returns:
- Future monthly expense at retirement: ~₹2,58,000
- Required retirement corpus: roughly ₹4-4.5 crore
- Required monthly SIP to build it: roughly ₹35,000-40,000/month
Your own numbers will differ — but this is the shape of the calculation.
Step 5: Design the Withdrawal Structure, Not Just the Number
A corpus number alone doesn't retire you safely. How you structure and withdraw from that corpus matters just as much:
- Sequencing — withdrawing from the right fund at the right time to avoid selling equity in a downturn.
- The ISG Framework — splitting the corpus into Income, Stability, and Growth buckets so short-term withdrawals never force a bad sale.
- Tax efficiency — structuring withdrawals to minimize your capital gains tax each year.
This is where a calculator gives you the target, but a structured plan gets you there safely. Our Retirement Planning and SWP Planning services are built specifically around this two-part problem.
Don't Wait Until You're Close to Retirement
The earlier you calculate your number, the more room you have to adjust — through a higher SIP, a longer runway, or a revised lifestyle target. If you're 15-20 years away from retirement, this is the ideal window to build the ISG Framework into your portfolio from the start.
Ready to see your own number? Try the Retirement Corpus Calculator now, or book a free consultation to walk through it together.
