Lumpsum Calculator – One-Time Investment Returns

QUICK REFERENCE

What ₹1 lakh grows to

A one-time investment of ₹1,00,000, compounded once a year, before inflation and tax. At 12% it roughly triples in ten years and grows seventeen-fold in twenty-five: time does more of the work than the rate.

Values rounded to the nearest rupee. For other amounts, scale: ₹5 lakh is five times each figure.

HOW IT WORKS

How a lumpsum investment grows

A lump sum is money invested once and left alone. Each year it earns a return on everything already there, including last year's gains, so the growth speeds up over time. The calculator uses the standard compound-growth formula:

The default example invests ₹1 lakh at 12% for 10 years. It grows to ₹3,10,585, a gain of ₹2,10,585. That headline is the figure most calculators stop at, but it overstates what the money will do for you, for two reasons.

Inflation: what the money is worth in today's rupees

Prices rise, so a rupee in ten years buys less than a rupee today. The calculator divides each year's value by the growth in prices over the same period. At 6% inflation, the ₹3,10,585 is worth ₹1,73,429 in today's money. Your 12% return is really about 5.66% a year in real terms, because (1.12 ÷ 1.06) − 1 is 5.66%. The same arithmetic shows why large future targets need care: ₹1 crore in 20 years, at 6% inflation, buys what ₹31,18,047 buys today.

Tax: what you keep when you sell

For an equity mutual fund, gains on units held more than 12 months are long-term capital gains, taxed at 12.5% on the gain above ₹1.25 lakh in a financial year, plus 4% cess. Gains on units held 12 months or less are short-term, taxed at 20% plus cess. On the default example the long-term tax is ₹11,126, so you keep ₹2,99,459. A bigger investment feels it more: ₹5 lakh at 12% for 15 years grows to ₹27,36,783 and pays ₹2,74,532 in tax. The calculator assumes the whole investment is sold in one go and you have no other gains that year; debt funds and fixed deposits are taxed at your income-tax slab instead. The rules come from the Income Tax Department and are rechecked after each Union Budget.

What return did I actually get?

The second mode works backwards. Enter what you invested, what it is worth now and how many years it took, and it gives the compound annual growth rate (CAGR): the steady yearly return that would have produced the same result. It is the fair way to compare investments held for different lengths of time. Doubling your money sounds like a 100% return, but over five years it is 14.87% a year; over ten it is 7.18%. Add inflation and the calculator shows the real return as well.

Lump sum or SIP?

With the same amount of money, a lump sum invested on day one has every rupee working for the full period, so in a rising market it usually ends ahead of the same money fed in monthly. A SIP trades some of that growth for averaging: buying a little every month means you never put everything in at a market peak. A lump sum suits money you already have, such as a bonus or a maturing deposit; a SIP suits saving out of income. Many investors do both, and some move a large lump sum into the market in instalments over a few months to spread the timing risk.

An expected return is an assumption

A fixed deposit gives you a known rate; equity does not. Long-run equity returns have averaged in the low teens for Indian indices, but individual years swing well above and below that, and past returns do not guarantee future ones. Try the calculator at a few rates, say 8%, 10% and 12%, to see the range of outcomes rather than relying on a single number. For comparison, ₹1 lakh in a 7% deposit for ten years becomes ₹1,96,715, which is ₹1,09,845 in today's money before tax.