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Retirement calculator: the corpus and the SIP to build it.
Enter today’s monthly expenses, your ages and returns before and after retirement. The calculator sizes the corpus and the SIP.
- Formula shown
- Free, nothing stored
- Share your result as a link
- Corpus by age
01How it works
In plain words.
Expenses grow with inflation until retirement. From then on the corpus pays a yearly withdrawal that keeps rising with inflation, while the rest earns the post retirement return. The corpus needed is the present value of those withdrawals at the real return. Your savings compound towards it, and the SIP fills the gap.
The formula
Yearly expense at retirement E = expenses x 12 x (1 + inflation)^years to goReal return = (1 + post return) / (1 + inflation) - 1Corpus = E x (1 - (1 + real)^-years in retirement) / realSIP = (corpus - savings grown) x i / ((1 + i)^n - 1)02Worked example
The default numbers, by hand.
Age 28 to 55, Rs 50,000 a month today, 6% inflation: expenses at 55 are about Rs 2.4 lakh a month. Funding them to 85 at 8% after retirement needs about Rs 6.58 crore; with Rs 5 lakh saved growing at 12%, the SIP is about Rs 25,800 a month.
| Input | Value |
|---|---|
| Age now | 28 |
| Retirement age | 55 |
| Plan until age | 85 |
| Monthly expenses today | ₹50,000 |
| Savings so far | ₹5,00,000 |
| Inflation a year | 6% |
| Return before retirement | 12% |
| Return after retirement | 8% |
| Result | Value |
|---|---|
| Corpus needed at 55 | ₹6.58 Cr |
| Monthly SIP from today | ₹25,752 |
| Monthly expenses at 55 | ₹2,41,117 |
| Current savings grow to | ₹1.07 Cr |
| The 25x check (4% rule) | ₹7.23 Cr |
03Key concepts
What to know before you use it.
The 4% rule
Research on US data (Bengen 1994; the Trinity study, 1998) found that withdrawing 4% of the starting portfolio, raised for inflation each year, lasted 30 years in most historical periods for portfolios with at least half in stocks. It is a US result and a rule of thumb; the card shows 25 times the first year’s expenses as a cross check.
Healthcare
Medical costs have often risen faster than headline inflation. A separate health cover and a higher inflation figure for medical spending are common ways to plan for it.
Good to know
- A few extra working years change the result twice: more years of saving and fewer of withdrawing.
- NPS, EPF and PPF balances count towards the savings figure.
04Assumptions
What the calculator assumes.
- Constant returns and inflation; withdrawals at the end of each year.
- No pension, rent or other income in retirement; no tax.
Sources, checked 12 Oct 2026
- Cooley, Hubbard and Walz (Trinity University), Retirement Savings: Choosing a Withdrawal Rate That Is Sustainable, AAII Journal, February 1998
- William Bengen, Determining Withdrawal Rates Using Historical Data, Journal of Financial Planning, October 1994
- RBI, monetary policy framework: CPI inflation target of 4% within a band of 2% to 6%, renewed for 1 Apr 2026 to 31 Mar 2031
05Questions
Asked about the Retirement planner.
How much corpus do I need to retire in India?
Enough to fund your expenses, rising with inflation, until the age you plan for. The calculator works it out from today’s expenses; the 25x card gives a quick cross check.
What is the 4% rule?
A rule of thumb from US research: withdraw 4% of the corpus in the first year and raise it with inflation; historically that lasted about 30 years in most periods. It is not a guarantee, and the evidence is from US markets.
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06Keep going
Learn the idea, see it applied.
More goal planning calculators
Education only, not investment advice. RupeeCase is a technology platform operated by QC Alpha Technologies Pvt Ltd; it is not a fund, a PMS or a SEBI registered investment adviser. Model returns are back tested and not a promise of future returns. Figures carry the date they were checked.