What is the Retirement Planning Calculator?
A retirement planning calculator estimates how large a corpus you need to stop working and still cover your living expenses for the rest of your life. Because prices keep rising, the expenses you have today will be far higher by the time you retire — so the calculator first inflates your current spending to its future value, then works out the lump sum required to fund those inflation-rising withdrawals throughout retirement.
How does it work?
You enter your age, planned retirement age, life expectancy, current monthly expenses, expected inflation, risk profile and any existing savings. The calculator inflates today’s expenses to your retirement date, then treats your retirement years as a stream of withdrawals that themselves grow with inflation. It discounts that stream at your post-retirement return to find the corpus needed on day one of retirement, grows your existing savings to that date, and shows the remaining gap. You can also turn on the optional SIP estimate to see the monthly investment that would bridge the gap.
Formula
E_R = E₀ × (1 + g)^Y; Corpus = (E_R × 12) × [1 − k^D] / [1 − k], where k = (1 + g) / (1 + r)
- E₀ = current monthly expenses
- g = annual inflation rate
- Y = years until retirement
- E_R = monthly expenses at retirement
- r = post-retirement annual return
- D = years to fund in retirement
Example calculation
A 30-year-old spending ₹50,000 a month, retiring at 60 and planning to age 85 with 6% inflation and a balanced profile needs roughly ₹7.3 crore. By then ₹50,000 of expenses has grown to about ₹2.87 lakh a month — which is exactly why a corpus that looks enormous in today’s money is simply what those everyday expenses cost in the future.
Benefits
- Turns vague worry into a concrete target by sizing the exact corpus you need.
- Makes inflation tangible — you see how everyday expenses balloon over the decades.
- Compares conservative, balanced and aggressive profiles so you can see how asset allocation changes the goal.
Limitations
- Assumes steady inflation and returns; real markets and prices fluctuate.
- Ignores taxes and other income such as pension, rent or EPF.
- A single life expectancy is an estimate — many people plan for a buffer beyond it.
Conclusion
Retirement planning is really a race between your corpus and inflation. Use this calculator to fix a realistic target, see how your risk profile moves it, and — if you turn on the SIP estimate — translate that target into a monthly investment you can start today. Once you have built (or inherited) a corpus, switch to the Retirement Income Calculator to see how long it lasts and what monthly income it can safely support.