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How to calculate lumpsum investment returns

Updated 2026-11-13

Quick answer

A lumpsum grows as P × (1 + r)^t. ₹1,00,000 invested for 10 years at 12% becomes 1,00,000 × 1.12^10 = ₹3,10,585, a gain of ₹2,10,585. At a steady 12% an amount roughly doubles every six years.

Steps

  1. Take the amount you will invest once. Here it is ₹1,00,000.
  2. Write the yearly return as a decimal: 12% is 0.12, so 1 + r = 1.12.
  3. Raise 1.12 to the number of years: 1.12^10 = 3.1058.
  4. Multiply by the amount: 1,00,000 × 3.1058 = ₹3,10,585.
  5. Subtract the amount invested to get the gain, ₹2,10,585, or enter the numbers in the lumpsum calculator.

How the years change the result

At 12% the same ₹1,00,000 becomes ₹1,76,234 after 5 years, ₹3,10,585 after 10 years, ₹5,47,357 after 15 years and ₹9,64,629 after 20 years.

Each extra five years multiplies the amount by about 1.76, so the later years add far more rupees than the early ones. This is compounding: the return is earned on the growth as well as on the original amount.

How the return changes the result

Over 10 years, ₹1,00,000 grows to ₹2,15,892 at 8%, ₹2,59,374 at 10% and ₹3,10,585 at 12%. A few points of return make a large difference over a long time, so compare options on their likely return after charges and tax, and keep the assumption modest.

Lumpsum or SIP

A lumpsum works if you already have the money, because all of it is invested from day one. If you earn month by month, a SIP is how you invest. The SIP vs lumpsum guide compares the two with the same numbers.

Try it yourself

Common questions

What is the lumpsum formula?

Future value = P × (1 + r)^t, where r is the yearly return as a decimal and t is the number of years.

How long does money take to double?

At a steady 12% it takes a little over six years. The rule of 72, 72 divided by the return, gives a quick estimate.

Is the return guaranteed?

No. Only a few products, such as some fixed deposits, state the return in advance. Market investments vary.

Should I invest everything at once?

That is a personal decision about risk. Some people split a lump sum into parts over a few months. Tax and charges also matter.

Also read: SIP vs lumpsum: which suits you, with numbers, How compound interest works, simple vs compound