How to use the Retirement Corpus Calculator
- Enter what you spend each month today, including rent or EMI if you will still pay it in retirement.
- Enter the inflation rate you expect, the years until you retire and the years you want the money to last.
- Enter your expected return after retirement, which is usually lower and safer, and before retirement, while you are still investing.
- Read the corpus, your monthly expense at retirement and the SIP required. Try different years to see the effect of starting earlier.
Formula used
Annual expense at retirement X = today’s expense × 12 × (1 + inflation)ⁿ. Corpus = Σ X × ((1 + inflation) ÷ (1 + post-retirement return))ᵏ for k = 0 to span − 1. SIP = corpus ÷ [((1 + j)ᵐ − 1) ÷ j × (1 + j)], with j the monthly pre-retirement return.
Worked example
Here is the Retirement Corpus Calculator worked through with the example values shown above, so you can check each step by hand.
| Inputs | |
|---|---|
| Monthly expenses today | ₹50,000 |
| Inflation (per year) | 6 % |
| Years until retirement | 25 years |
| Years in retirement | 25 years |
| Return after retirement (per year) | 8 % |
| Return before retirement (per year) | 12 % |
| Result | |
| Corpus needed at retirement | ₹5,19,11,228 |
| Monthly expense at retirement | ₹2,14,594 |
| Monthly SIP needed from today | ₹27,356 |
Corpus and SIP by years left
With the other default inputs unchanged, this shows how starting earlier lowers the monthly SIP needed.
| Years until retirement | Corpus needed at retirement | Monthly SIP needed from today |
|---|---|---|
| 10 years | ₹2,16,60,742 | ₹93,229 |
| 15 years | ₹2,89,86,958 | ₹57,448 |
| 20 years | ₹3,87,91,089 | ₹38,824 |
| 25 years | ₹5,19,11,228 | ₹27,356 |
| 30 years | ₹6,94,68,933 | ₹19,680 |
How the corpus is worked out
Suppose you spend ₹50,000 a month today and expect 6% inflation. In 25 years the same lifestyle costs about ₹2,14,594 a month, or ₹25,75,122 a year. That is the withdrawal in your first year of retirement.
The calculator then assumes the withdrawal keeps rising with inflation, while the remaining corpus earns 8% a year. For 25 years of retirement, the corpus needed at the start is ₹5,19,11,228. To build it over 25 years at 12%, you would need to invest about ₹27,356 a month.
Why inflation matters more than most people expect
Because inflation compounds, a small change has a large effect. With the other inputs unchanged, 5% inflation needs a corpus of ₹3,69,77,240, 6% needs ₹5,19,11,228 and 7% needs ₹7,29,76,435.
The return after retirement matters just as much. A safer portfolio that earns less needs a bigger corpus, because the money has to last while also keeping up with rising prices.
Starting early versus late
The table below shows the same plan with a different number of years left. Starting 30 years before retirement needs a monthly SIP of ₹19,680. With 20 years left it is ₹38,824, and with only 10 years left it is ₹93,229. The corpus changes too, because with fewer years the expenses have had less time to inflate.
The cost of waiting is large, because time is what lets small contributions compound.
What this estimate leaves out
It does not include taxes, healthcare shocks, a pension or other income, or the sale of any property. It assumes a constant return and a constant inflation rate, which real life does not offer. Your spending will also change as you age, often falling in some areas and rising in healthcare.
Use the result as a starting target and review it every year. A qualified financial planner can help you build a plan that fits your situation.
Frequently asked questions
How much money do I need to retire?
It depends on your expenses, inflation, the years you will need the money and your returns. This calculator estimates it from those inputs.
What inflation rate should I use?
Many planners use roughly 5% to 7% for general expenses in India. Healthcare often rises faster. Try several values.
Why is the post-retirement return lower?
After retirement most people hold safer investments, so returns are usually lower than during the saving years.
Does the corpus run out exactly at the end?
The calculator sizes the corpus so that it just covers the withdrawals through the years you entered. A safety margin is wise.
Are taxes included?
No. Taxes on returns and withdrawals reduce the money you can use.
Should I include my EPF or NPS?
You can subtract what you already have, or expect from those, from the corpus needed to find how much more you must save.
This calculator gives estimates for information only. Actual figures from a bank, employer, tax authority or doctor may differ. It is not financial, tax, legal or medical advice.