Finance & Investment · Interest
Compound Growth Calculator
Project how a sum grows when it compounds at a yearly growth rate — for a fund, a business or any investment whose return you expect rather than know. Add a yearly top-up, and see a cautious, an expected and an optimistic case together, with the growth multiple and the time to double.
Your inputs
₹ 1 lakh
Your result Live
Expected Value
₹4,17,725
₹1,00,000 growing 10% a year for 15 years
- Cautious Case (8% a year)
- ₹3,17,217
- Optimistic Case (12% a year)
- ₹5,47,357
- Growth Earned (expected)
- ₹3,17,725
- Growth Multiple (expected)
- 4.18×
- Time to Double (expected rate)
- 7.3 years
- Rule of 72 Estimate
- 7.2 years
- Starting amount · 24%₹1,00,000
- Growth · 76%₹3,17,725
Year-by-year growth
15 rowsCautious and optimistic cases are 2 percentage points below and above the expected 10.0% growth. Real returns are never steady, so treat all three as illustrations.
An estimate from the assumptions you entered, not a guaranteed outcome.
How this is calculated
V = P × (1 + g)^t + Σ T × (1 + g)^(t − tₖ)
- V
- Value at the end
- P
- Starting amount
- g
- Yearly growth rate (decimal)
- T
- Yearly top-up
- t
- Time in years
Compound growth means each year's growth is added to the amount, so the next year's growth is earned on a bigger base. Unlike a bank deposit, an investment's growth rate is an expectation, not a promise — so this calculator shows a cautious and an optimistic case around the expected one. The gap between them widens every year, which is the real lesson: over long periods a 2-point difference in yearly growth changes the result enormously.
Assumptions & sources
- Growth is the same every year and is added once a year (yearly compounding); real returns vary.
- A top-up is the same amount each year, at the beginning or the end of the year.
- Costs and tax are not deducted; use the Fee Impact or Post-Tax Return calculators for those.
- A final part-year grows by the matching fraction of a year, and gets no top-up at the end timing.
- 1Investments (Bodie, Kane & Marcus), chapters on returns, compounding and the time value of money — McGraw-Hill
- 2CFA Program Curriculum — Quantitative Methods: The Time Value of Money — CFA Institute
Calculator ID FIN-INT-CG-001 · version 1.0.0
Common questions
How is compound growth different from simple growth?
Simple growth adds the same amount every year (10 % of the starting sum). Compound growth adds a percentage of the whole current amount, so the gains get larger each year. ₹1,00,000 at 10 % for 15 years becomes ₹2,50,000 with simple growth but ₹4,17,725 with compound growth.
What is the rule of 72?
A quick way to estimate how long money takes to double: divide 72 by the yearly growth rate. At 8 % it is about 9 years; the exact answer is 9.01. It works best for rates between about 6 % and 10 %.
Why show a cautious and an optimistic case?
Nobody knows the future growth rate. Seeing the result at two points either side of your expectation shows how sensitive it is, and helps you plan for a result below the expected one.
What is the difference between this and the Compound Interest Calculator?
The Compound Interest Calculator is for interest paid on a deposit — any compounding frequency, regular deposits, withdrawals and rate changes. This one is for an expected growth rate on an investment, with three scenarios.