Lumpsum Calculator
What one investment becomes after a run of years.
Everything runs inside your browser. Your files never leave your device.
Result
Ask about Lumpsum Calculator
Questions about what this tool does, which option to pick, or what it can and cannot handle.
The question you type here is sent to an AI provider to be answered — your files and whatever you put in the tool above are not, and the assistant cannot see them. Answers are generated and can be wrong. The tool itself is not guessing: it runs deterministic code on your device.
About the Lumpsum Calculator
A lumpsum investment is one amount, put in once and left alone for a number of years. This is the simplest projection in personal finance and the one that shows compounding most clearly, because nothing else is happening to muddy it.
The figure that repays attention here is the doubling time, printed alongside the result. At twelve per cent money doubles roughly every six years; at eight per cent it takes about nine. That difference sounds modest stated as four percentage points and is enormous stated as outcomes — over twenty-four years the twelve per cent case doubles four times and the eight per cent case doubles under three, which is the difference between sixteen times your money and about six.
The year-by-year column is there to make the shape visible. Growth on a single amount is not a line but a curve that stays almost flat for years before turning upward, and most of the final value appears in the last third of the term. Anyone who has abandoned an investment at year four because "it has not done much" has met the flat part of that curve and mistaken it for the whole thing.
A caution on the rate. Historical averages for Indian equity indices sit in the low teens over long windows, but any particular decade can sit well below that, and the projection assumes the rate arrives evenly, which no market does. Run the number twice — once at the rate you hope for and once four points below it — and plan against the lower one.
How to use it
- 1Enter the amount you are putting in as a single payment.
- 2Set the return you expect, then note the doubling time the tool prints beside it.
- 3Read down the yearly column and see how late in the term most of the growth appears.
- 4Re-run at a materially lower rate and use that as the figure you plan against.
Questions
- Is a lump sum better than spreading the money out?
- Statistically a lump sum wins more often, because the money is exposed to growth for longer. The case for spreading it is behavioural rather than mathematical: it removes the risk of committing everything the week before a fall, which is the thing that makes people abandon a plan.
- Why does the doubling time matter more than the rate?
- Because it converts an abstract percentage into a period you can picture. Six years versus nine years is a comparison anyone can hold in their head; twelve per cent versus eight per cent is not.
- Does this account for tax on the gain?
- No. The projection is pre-tax. What you owe depends on the instrument, how long you held it and which regime applies, none of which this knows about.
- What if I want to add to it later?
- Use the compound interest tool, which takes a starting amount and a monthly addition together, or the SIP tool if the additions are the main event.