Retirement Corpus Calculator

What This Retirement Corpus Calculator Does

This calculator estimates two things: how large a corpus you would need at retirement to sustain your current monthly expenses (adjusted for inflation) for the rest of your expected lifespan, and the monthly SIP required between now and retirement to build that corpus.

The Formula

First, today's monthly expense is inflated forward to your retirement age. That future monthly expense is then treated as a growing annuity you'll draw down through retirement, discounted at the "real rate" - your post-retirement investment return minus inflation - to find the corpus needed at the moment you retire. Finally, that corpus becomes the target in the same goal-SIP formula used elsewhere on this site, solved using your expected pre-retirement return and the years remaining until retirement.

How to Use It

Enter your current age, planned retirement age, life expectancy, and today's monthly expenses. Then set three rate assumptions: expected inflation, expected returns before retirement (typically higher, equity-heavy investments), and expected returns after retirement (typically more conservative). The calculator shows your projected monthly expense at retirement, the total corpus you'll need, and the monthly SIP required to build it.

Why the Pre- and Post-Retirement Returns Differ

Most people invest more aggressively while working, since they have time to ride out market volatility, and shift toward safer, income-generating investments after retirement, when the priority moves from growth to preserving capital. Using two separate rate inputs, rather than one blended assumption, keeps the calculation closer to how retirement planning actually works in practice.

Who This Is For

Anyone who wants a concrete, numbers-based starting point for retirement planning - a target corpus and a monthly SIP figure - rather than a vague sense that they "should be saving more".

Quick Example

A 30-year-old spending ₹50,000/month today, retiring at 60 with a life expectancy of 85, at 6% inflation and a 7% post-retirement return, would need a future monthly expense of roughly ₹2,87,175 covered - translating into a substantial required retirement corpus, and a monthly SIP figure the calculator works out automatically at your chosen pre-retirement return.