Retirement Corpus Calculator

One question only: how much money do you need on the day you retire? Enter what you spend now, when you plan to stop working, and how long the money must last.

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How to use this calculator

  1. Enter monthly expenses today — What your current lifestyle costs each month.
  2. Enter years until retirement
  3. Enter years the money must last — From retirement to your planning age. Be generous.
  4. Enter expected inflation
  5. Enter return during retirement — What the corpus earns while you are drawing from it.
  6. Read the result — it updates as you type.

The formula used

Corpus = E × [ 1 − (1 + rreal)−n ] ÷ rreal  where E = today's expense × (1 + inflation)y

E
Monthly expense on your first day of retirement
n
Months of retirement to fund
r_real
Monthly real return = (1 + return) ÷ (1 + inflation) − 1
y
Years until retirement

This is the present value of an inflation-linked annuity. Using the real return rather than the nominal one is what allows the withdrawals to rise with prices every year without needing a separate calculation for each year.

Worked example

You spend ₹60,000 a month, retire in 25 years, and want the money to last 25 years at 6% inflation and 8% returns.

  • Expense at retirement₹60,000 × 1.06²⁵ = ₹2,57,512 a month
  • Real return(1.08 ÷ 1.06) − 1 = 1.887% a year
  1. Monthly real rate = 0.156%
  2. Annuity factor for 300 months ≈ 239.47
  3. Corpus = ₹2,57,512 × 239.47 ≈ ₹6.17 crore

Large, but note that ₹2.58 lakh a month in 25 years buys exactly what ₹60,000 buys today. The number is big because rupees will be smaller.

Why the number is so large — and why that is fine

Two things inflate a retirement corpus: decades of inflation before you retire, and decades of inflation during retirement. Both are unavoidable, and both are why a figure that feels absurd today is simply realistic.

The corpus is not sitting in cash

It keeps working. At 8% while you withdraw, roughly half of everything you spend in retirement comes from returns earned during retirement, not from the original pot.

The assumption that matters most

The gap between your return and inflation — the real return — drives everything. At 8% against 6% you need one figure; at 7% against 7% the real return is zero and the corpus required jumps sharply. Be conservative here.

What to do with the number

Take it to the Retirement Calculator, which converts it into the monthly investment needed from today — usually a far less frightening figure.

Tips and common mistakes

Getting more out of it

  • Subtract any pension or rental income from your monthly expenses first, so the corpus only covers the shortfall.
  • Add ten years to the "money must last" field to see what longevity risk costs — it is usually less than people fear.

Mistakes to avoid

  • Multiplying future monthly expenses by the number of months. That badly overstates the need, because the corpus keeps earning.
  • Using today's expenses as the retirement figure without inflating them first.
  • Assuming spending falls in retirement. Travel and healthcare often replace commuting and EMIs.

Frequently asked questions

How many times my annual expenses should the corpus be?

This calculator shows the multiple in the results. It typically lands somewhere between 25 and 35 times current annual spending, depending on your assumptions and how long the money must last.

Should I plan for the corpus to run out?

This model ends at close to zero. If you want to leave an inheritance or protect against living longer than planned, add 10–15 years to the "years the money must last" field.

Are healthcare costs included?

Only if they are in your monthly expenses figure. Medical inflation typically runs well above general inflation, so consider adding a separate buffer.

What about my pension or rental income?

Subtract that income from your monthly expenses before entering them. The corpus then only needs to cover the shortfall.

Disclaimer: These calculators are for educational and informational purposes only. Results are estimates based on the inputs provided and should not be considered financial, investment, tax, or legal advice.