FINBIZTOOLS
Investment Growth Calculator
Estimate how an investment could grow when you start with a lump sum and add a fixed amount every month. Enter the starting amount, monthly contribution, expected annual return and duration to see total contributions, estimated gains and the final value, with a year-by-year table.
Private by design · Inputs and downloads stay in your browser
Changes the currency symbol and number format only. Amounts are not converted.
Monthly contributions are added at the start of each month, and the expected return is a constant assumption divided by 12. This is a general investment-growth projection, not a substitute for the SIP Calculator's India-oriented SIP illustration.
How to use the Investment Growth Calculator
- Enter the initial investment (0 is allowed if you are starting from scratch).
- Enter the monthly contribution you plan to add.
- Enter the expected annual return as a percentage, from 0% to 50%.
- Enter the investment period in whole years, then select Calculate to see the year-wise growth table.
Use the currency selector above the inputs to change the symbol. It changes the display only and does not convert amounts.
How this differs from a SIP
This calculator combines a starting lump sum with ongoing monthly contributions, which is a common international investment pattern: you begin with savings already set aside, then keep adding to it.
It is deliberately more general than the SIP Calculator, which models a pure monthly instalment plan without an initial amount. Use this calculator when a starting balance is part of the picture.
How the calculation works
Investment growth formula
Monthly rate: r = annual return % ÷ 1200
Each month: balance = (balance + monthly contribution) × (1 + r)
- The starting balance is the initial investment.
- The contribution is added at the start of every month, before that month's return is applied.
Total contributions is the sum of every monthly contribution. Estimated gains is the final value minus the initial investment minus total contributions. The year-wise table uses the same monthly steps as the summary, so the rows always add up to the totals shown.
Investment growth calculation example
Starting with 10,000 and adding 500 every month for 10 years, at an assumed 8% annual return:
| Initial investment | 10,000 |
|---|---|
| Monthly contribution | 500 |
| Expected annual return | 8% |
| Investment period | 10 years |
| Initial investment | 10,000 |
|---|---|
| Total contributions | 60,000 |
| Estimated investment gains | 44,279.24 |
| Estimated final value | 114,279.24 |
Amounts are shown without a currency symbol because the arithmetic is identical in any currency. The currency selector only changes the symbol and number format; it never converts amounts.
Assumptions and limitations
Assumptions
- The expected return is constant and applied monthly (the annual rate divided by 12).
- The monthly contribution is a fixed amount added at the start of each month.
- No adjustment for fees, taxes or inflation.
Limitations and why results can differ
- Real investment returns vary year to year and can be negative; a constant assumed rate is a simplification.
- The calculator does not model irregular or missed contributions, or a contribution that changes over time.
- Past or assumed growth does not indicate future performance.
Frequently asked questions
Are the estimated returns guaranteed?
No. The annual return is a constant assumption you choose. Actual investment returns vary and can be negative.
Does the calculator include fees?
No. Fund charges, platform fees, taxes and inflation are not deducted from the result.
How are the monthly contributions treated?
Each contribution is added at the start of its month, and that month's return is then applied to the new balance.
Can I use this with no starting amount?
Yes. Enter 0 as the initial investment to project contributions alone.
How is this different from the SIP Calculator?
The SIP Calculator models a pure monthly investment plan with no starting lump sum. This calculator lets you combine a starting amount with ongoing monthly contributions.
Methodology
Inputs are validated: initial investment from 0 to 1,000,000,000, monthly contribution from 0 to 10,000,000, expected annual return from 0% to 50%, and investment period as a whole number of years from 1 to 50.
The engine steps through every month: the contribution is added first, then that month's return (the annual rate divided by 12) is applied to the new balance. The year-wise table accumulates the same monthly steps as the headline totals, so the rows always reconcile with 'Total contributions' and 'Estimated investment gains'. Rounding is applied only for display. The calculation runs in your browser and inputs are not sent to a server.
Last reviewed:
Disclaimer
Results are estimates based on the assumptions you enter and do not guarantee future returns. This page is for information only and is not financial, investment or tax advice. Read the full Disclaimer.
Explore this topic
This tool is part of Investing and Saving.
A common order: set a savings goal, project growth with regular or lump-sum investing, then adjust for inflation.