Reverse Lump Sum Calculator

Find the required initial lump sum investment to achieve a target financial goal.

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How Much Money Today Reaches a Future Goal?

The reverse lump sum calculator works out the one-time investment needed today to reach a target amount at a future date. It solves the compounding equation in reverse: the required amount is the target divided by the growth factor over the holding period. On the defaults, ₹1 crore needed in 15 years at a 12% CAGR, a single investment of about ₹18.3 lakh today is enough, with the remaining ₹81.7 lakh coming from growth. The mechanics behind that are covered in lump sum investing.

Time is the biggest lever. Stretching the same ₹1 crore target from 15 to 20 years cuts the required amount to about ₹10.4 lakh, and at 30 years it falls to roughly ₹3.3 lakh, not because the goal shrinks, but because the money compounds for longer. That same sensitivity is the risk: one purchase is fully exposed to the market level on the day you invest, and the shorter the horizon, the more that single day decides the outcome. The assumed CAGR should be scaled to the horizon, not taken from a bull-market period.

Use it when the money already exists: a bonus, maturity proceeds, a property sale or an inheritance. When the amount has to be built from monthly income instead, the reverse SIP calculator solves the same problem instalment by instalment, and the SIP vs lump sum comparison shows how the two funding routes differ. To check what a one-time investment grows into instead, run it forward in the lump sum calculator.

Popular Reverse Lump Sum Calculations

Click on any of the popular search scenarios below to load the calculator with pre-configured values:

Frequently Asked Questions

What is a reverse lump sum calculator?
It computes the one-time investment required today to reach a target amount at a chosen future date, given an expected annual return. A regular lump sum calculator projects forward from an invested amount; the reverse version starts from the goal. For example, ₹1 crore in 15 years at 12% needs about ₹18.3 lakh today, because the rest is supplied by compounding.
How much must I invest today to get ₹1 crore?
At an assumed 12% CAGR the answer is about ₹18.3 lakh for a 15-year horizon, roughly ₹10.4 lakh for 20 years and about ₹3.3 lakh for 30 years. The required amount falls quickly with time because compounding works on the whole balance; it also depends heavily on the return assumption, so test the figure at a lower rate as well.
Lump sum or SIP, which route needs less money?
The lump sum, because the entire amount compounds from day one. Reaching ₹1 crore in 15 years at 12% takes about ₹18.3 lakh as a one-time investment, against roughly ₹37.8 lakh in total if it is paid in through a monthly SIP, though the SIP route matches how salaried income arrives. The SIP vs lump sum comparison weighs the two approaches, including the entry-timing risk of investing everything at once.
Should I assume a 12% return for a short horizon?
No, a 10-12% assumption is a long-run figure for Indian equity, and over 3-5 years actual returns can land far away from any average, including negative. If the goal is only a few years away, a lower assumed rate plus a safer portfolio gives a more honest required amount, which is why the planner here works best over horizons of at least five to seven years.

Formula & Mathematical Approach

Calculates the initial present value investment needed to grow to a target future corpus.

Required Principal=Target Corpus(1+Return Rate100)Years\text{Required Principal} = \frac{\text{Target Corpus}}{\left(1 + \frac{\text{Return Rate}}{100}\right)^{\text{Years}}}
Show Plain Text / Excel Formula
Required Principal = Target Corpus / (1 + Return Rate / 100) ^ Years

Key Assumptions

  • Growth is compounded annually at a constant rate.
  • No interim transactions or withdrawals occur.