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About this tool
Find the retirement corpus you need and the monthly SIP to get there, with inflation-adjusted math and a year-wise plan.
The Retirement Corpus Calculator works out the lump sum you need on your retirement date and the monthly SIP that gets you there, by inflating today's expenses to your retirement year and then discounting the whole retirement period at the real return — (1 + post-retirement return) ÷ (1 + inflation) − 1 — as an annuity due. It is for anyone who knows roughly what they spend each month and wants a defensible target number rather than a round-figure guess. You also see how much of the target your existing savings already cover, and what a five-year delay in starting would cost.
Open Retirement Corpus Calculator on AltFTool — it loads instantly in your browser.
Enter Current age, Retire at, Current monthly expenses and Existing retirement corpus, or tap a preset such as "Classic plan, 30".
Open Assumptions to set Plan till age (life expectancy), Inflation, Pre-retirement return and Post-retirement return.
Read the corpus-needed tile and Monthly SIP to get there, then press Copy plan for the year-wise build and drawdown.
The corpus is discounted at the inflation-adjusted return rather than a 25× or 30× rule of thumb, so a longer retirement or a lower post-retirement return changes the target properly.
Pre-retirement and post-retirement returns are entered separately, matching a portfolio that de-risks after you stop working.
It recomputes the SIP as if you started five years later and reports both the higher monthly figure and the extra total invested.
Enough to fund your inflation-adjusted annual expenses for every year from retirement to life expectancy, discounted at your real return. The calculator inflates today's monthly expense at your inflation rate — 6% by default — over the years to retirement, annualises it, then values that stream as an annuity due over the retirement period.
It is (1 + post-retirement return) ÷ (1 + inflation) − 1, and it is what your money earns after inflation eats into it. With the defaults of an 8% post-retirement return and 6% inflation the real rate is roughly 1.9%, which is why the required corpus is much larger than a simple 8% return would suggest.
Your existing corpus is first compounded forward at the pre-retirement return (12% by default) over the months to retirement; whatever gap remains against the target is divided by the future-value factor of a monthly annuity due at the same rate. If your existing savings already cover the target, the required SIP is zero.
The same gap has to be filled in 60 fewer months, so the required SIP rises sharply and the total amount you invest rises with it — the tool shows both numbers for a five-year delay. These are informational projections based on the rates you enter, not guaranteed outcomes; speak to a licensed financial adviser before acting on them.
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