Investment Growth Calculator | RetirePeace
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Journey step 2 · Build your corpus

Investment Growth Calculator

Estimate how your retirement investments could grow over time using one-time investments, regular SIP contributions, or both.

See how this calculation works

Your plan
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Tick SIP Top-Up to enable it, then set the increase (1–15%) and how often it applies. For example, 10% every 2 years raises your monthly SIP by 10% at the start of every second year.
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Return & duration
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Your results
Projected Corpus
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No one-time investments yet
Add lump sums such as an annual bonus, a policy maturity or a gift. Each is invested in the year you choose and grows with the rest.
Year
Amount
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Investment growth over time
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Projected value Total invested
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Year-by-year projection

Every row is a direct calculation. Contributions are added through the year and growth is the return earned on the balance. Highlighted rows include a one-time investment.

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Year Opening balance Contributions Investment growth Closing balance {{ r.year }}
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How your investment growth is calculated

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Understanding the Investment Growth Calculator

This calculator projects how a lump sum, a regular monthly investment, or a combination of the two could grow over time. It is the accumulation half of retirement planning: it answers how a pot is built, rather than how much you need or how it is drawn down.

It is useful for seeing how much of a final balance comes from money you paid in versus compounding, and for testing how sensitive that split is to your time horizon and assumed return.

What each input means

Starting investment
A lump sum invested at the beginning. It compounds for the entire period.
Monthly SIP
The amount invested every month. Each month’s contribution is added at the end of that month, so it compounds for the remaining months rather than the full year.
SIP top-up
An optional yearly increase to the monthly amount, applied at the start of each new year. It models contributions that rise as income rises, and can be set to repeat every one to five years.
Expected annual return (CAGR)
An effective annual growth rate, converted internally to a monthly rate so that growth compounds month by month.
Investment duration
How many years the projection runs, from 1 to 60.
One-time investments
Optional lump sums added in a chosen future year, such as a bonus or a maturity. They are added at the start of that year, so they compound for the remainder of the projection.

How to read your result

Projected corpus
The closing balance at the end of the final year, under your assumptions.
Total amount invested
Every unit of money you actually paid in, the starting amount plus all contributions. It contains no growth.
Estimated investment growth
Projected corpus minus total invested. This is the compounding.
Growth multiple
Projected corpus divided by total invested, a quick sense of how hard the compounding worked over the period.
Year-by-year table
Opening balance, contributions, growth and closing balance for each year, so you can see exactly where the total comes from.

The maths behind it

The effective annual return you enter is converted to a monthly rate, then applied month by month. Within each year the opening balance carries over from the previous year, any one-time investments are added first so they compound for the rest of the period, and the monthly contribution is added at the end of each month. If a top-up is enabled, the monthly amount is raised at the start of the following year.

Assumptions and limitations

  • Every projection applies a single fixed return to each year. Real markets rise and fall, so a portfolio that averages the same return can still finish somewhere quite different, especially once withdrawals begin and a poor run arrives early.
  • Tax, platform fees, fund charges and transaction costs are not modelled. A real-world net outcome will be lower than a gross projection.
  • Returns and inflation are assumptions you choose, not forecasts. The output is only ever as reliable as the numbers you put in.
  • Figures are shown in the currency you select. No exchange-rate movement is modelled.
  • This is general educational information to help you understand your own numbers, not personalised financial advice.

Related calculators

Learn the concepts behind this calculator

The full Retirement Learning Centre covers withdrawals, inflation, FIRE and drawdown strategy, and how RetirePeace calculates documents every modelling convention used on this page.

More questions about assumptions, withdrawals and how these projections work are answered in the retirement planning FAQ.

The calculations provided by RetirePeace are intended for educational and planning purposes only. Investment returns, inflation, and future market conditions are uncertain. Actual outcomes may differ. This is not financial, investment, tax, or legal advice.