Lumpsum calculator — project a one-time investment year by year

How to use the lumpsum calculator

1. Enter the One-time investment, the amount you invest on day one.
2. Enter the Expected return (per year) as a percentage. This is your assumption.
3. Enter the number of Years. Decimals such as 7.5 are allowed.
4. Choose a Currency. Rupees are the default; the maths works the same in dollars, pounds or euros.
5. Read the Maturity value, Amount invested, Estimated gain and Growth multiple. The chart shows the value climbing year by year, and the Year-by-year value table, which you can download as CSV, lists the value and the gain at the end of each year.

What it does and when to use it

You may come into a large sum at one time: a yearly bonus, a matured deposit, money from selling a property, or savings you have kept in a bank account. Before you decide what to do with it, it helps to see what it could become if it grew at a steady rate. The lumpsum calculator gives you that picture in seconds.

People use it to:

• Picture a goal. If you invest ₹5 lakh today for a child’s education 15 years away, what might it be worth at 8%?
• Compare assumptions. The gap between a 7% and a 12% return over 20 years is large. Running both shows how much the outcome depends on the rate.
• Compare with a SIP. If you could also invest the same total in monthly parts, the SIP calculator shows that route, and the step-up SIP calculator covers a SIP that rises each year.
• Check a doubling claim. The growth multiple shows how many times the money has grown. The rule of 72 calculator gives a quick estimate of the years needed to double at any rate.

SEBI’s investor FAQ notes that investments in mutual fund schemes can be made either as a lump sum, meaning a one-time payment, or through a SIP. This calculator models the first case under a simple assumption: a constant yearly return.

How it works

The calculator uses the compound growth formula with yearly compounding:

Maturity value = A × (1 + r)^t

• A is the one-time investment.
• r is the expected yearly return as a decimal, so 12% becomes 0.12.
• t is the number of years, which may include a fraction.

Compound growth means each year’s gain is added to the amount invested and earns a return itself in later years. Investor.gov describes compound interest as interest paid on the principal and on interest already earned. The same idea applies to an assumed investment return.

The other outputs follow from the maturity value:

• Estimated gain = maturity value − amount invested.
• Growth multiple = maturity value ÷ amount invested. A multiple of 3.11 means the money is about three times what you put in.

Step by step. Take ₹1,00,000 at 12%:

• After year 1: 1,00,000 × 1.12 = ₹1,12,000.
• After year 2: 1,12,000 × 1.12 = ₹1,25,440.
• After year 3: 1,25,440 × 1.12 = ₹1,40,492.80.

Each year’s gain is larger than the year before because it is calculated on a bigger balance. In year 1 the gain is ₹12,000; in year 10 it is about ₹33,277 (from ₹2,77,307.88 to ₹3,10,584.82).

For part years the formula uses the fractional power directly. With t = 2.5, the value is 1,00,000 × 1.12^2.5 = ₹1,32,753.22.

Worked examples

These figures come from the calculator’s own function.

₹1 lakh for 10 years at 12%. One-time investment ₹1,00,000, expected return 12%, 10 years:

• Maturity value: ₹3,10,584.82
• Amount invested: ₹1,00,000.00
• Estimated gain: ₹2,10,584.82
• Growth multiple: 3.11 ×

Selected rows from the table:

The value roughly doubles between year 6 and year 7, close to what the rule of 72 suggests (72 ÷ 12 = 6 years).

₹5 lakh for 15 years at 8%. One-time investment ₹5,00,000, 8%, 15 years. Maturity value ₹15,86,084.56, estimated gain ₹10,86,084.56, growth multiple 3.17 ×. Notice that a lower return over a longer period can reach a similar multiple to a higher return over a shorter one.

$5,000 for 20 years at 7%. With the currency set to US dollars: maturity value $19,348.42 and estimated gain $14,348.42, a growth multiple of 3.87 ×. The value passes $10,000 in year 11 ($10,524.26).

Lumpsum versus spreading it out

A lumpsum puts all your money to work at once. If the assumed return is achieved, that gives it the most time to compound. The risk is timing: if prices fall soon after you invest, the whole amount falls with them. A SIP buys units at many different prices. SEBI’s FAQ gives a worked example showing how regular monthly investing averages the cost of units over a year.

This calculator cannot tell you which approach is right, because real markets do not deliver a steady yearly return. What it can do is show what the numbers look like under the rate you choose. If you plan to take money out regularly later on, the SWP calculator shows how long a corpus lasts at a given monthly withdrawal.

To check the return on an investment you already hold, use the investment return calculator, which works backwards from a start and end value to the yearly growth rate (CAGR).

Comparing different rates

Because the result depends so heavily on the rate, try the same amount and period at several returns. With ₹1,00,000 for 10 years, a 12% assumption gives ₹3,10,584.82. Try 8% and 10% on the calculator to see how quickly the outcome shrinks. The difference is not a forecast of what will happen; it shows how sensitive the answer is to one assumption.

For a deposit with a fixed rate and quarterly compounding, the FD calculator is more accurate than this tool, because it matches how Indian banks credit interest.

Limits and tips

• The return is an assumption, not a promise. Mutual fund investments are subject to market risks. No fund delivers the same return every year, and some years are negative.
• Yearly compounding only. The calculator compounds once a year. Bank deposits that compound quarterly or monthly will grow slightly faster at the same quoted rate.
• No tax, charges or inflation. The result is before capital gains tax, fund expenses and exit loads, and it is in future money. Use the inflation calculator to see what the maturity value may be worth in today’s money.
• No withdrawals or top-ups. The model assumes you invest once and leave the money untouched. For regular additions, the compound interest calculator handles monthly contributions.
• Use it for planning, not decisions alone. For advice on where to invest a large sum, speak to a SEBI-registered investment adviser.
• The calculation runs in your browser and nothing you enter is sent anywhere.